Abstract: A signal divider/combiner (11) and method combines first and second frequency signals received by microstrip patch antennas (58, 48). A first transmission line stub (28) blocks the second frequency signals on the first signal receiving path, and a second transmission line stub (20) blocks the first frequency signals on the second signal receiving path providing increased signal levels at a receiver input (10). In one embodiment, the transmission line stubs are open-circuit stubs and are positioned a quarter-wavelength from a combining junction (12) formed from stripline transmission lines (14, 32, 50). The transmission line stubs (28, 20) also reduce radiation of the first frequency signal by the second antenna as well as radiation of the second frequency signal by the first antenna. In one embodiment, the first and second frequency signals are the L1 and L2 signals provided by the Global Positioning System.

Abstract: A coplanar coupler for use with microstrip input and output ports includes a printed circuit substrate in which first and second metal input ports are formed on a top surface and cooperate with a metal layer on the bottom surface as microstrip lines, and first and second metal output ports formed on the top surface which cooperate with the metal layer on the bottom surface as microstrip lines. The metal layer on the bottom surface functions as a ground plane for the input ports and the output ports, the metal layer being removed in a coupler region underlying at least portions of the metal input and output ports and extending therebetween. First and second metal lines are formed on the bottom surface in the coupler region and function as a coplanar coupler for the input and output ports. Electrical vias in the substrate interconnect the ports and the coplanar coupler.

Abstract: A microstrip side-coupled directional coupler (20) uses inductive loading to achieve improved directivity. In one embodiment, short-circuited inductive stubs (26, 27) are connected to the coupled line (22) of the coupler (20). In a second embodiment, pairs of short circuited inductive stubs (34, 35) are connected respectively to the coupled line (32) and the primary transmission line (35) of a directional coupler (30). In a third embodiment, the primary transmission line (41) and the coupled line (42) of a coupler (40) are both centre loaded with short-circuited inductive stubs (43, 44) respectively.

Abstract: A delay circuit in which amplitude characteristic and delay time characteristic of the output signals do not have any ripple relative to the length of the transmission line is provided. The delay circuit includes a circuit that makes a part of signals distributed into two parts by the power divider (103) to be identical in amplitude and inverse in phase relative to the component of signals outputted from the terminal-a directly to the terminal-c of the circulator (104). By composing with the power combiner (107) both signals are offset each other at the output terminal. As a result, only the signals that are inputted from the input terminal (101) and transmitted through the circulator (104) and the open-ended transmission line (105) are outputted to the output terminal (102).

Abstract: A six port 3:1 power divider and combiner. The inventive divider/combiner includes first, second and third weakly coupled transmission lines. The first transmission line provides first and second ports at first and second ends thereof, respectively. The second transmission line provides third and fourth ports at first and second ends thereof, respectively and the third transmission line provides fifth and sixth ports at first and second ends thereof, respectively. In the illustrative embodiment, the first, second and third transmission lines are coupled to provide equal outputs at said second, fourth and sixth ports in response to an application of a signal at the first port. The first second and third conductors may be implemented with coaxial, stripline or microstrip type transmission lines. The looser coupling is very beneficial, especially in microstrip, to obtain high power capability and a manufacturable circuit.

Abstract: A six port 3:1 power divider and combiner. The inventive divider/combiner includes first, second and third weakly coupled transmission lines. The first transmission line provides first and second ports at first and second ends thereof, respectively. The second transmission line provides third and fourth ports at first and second ends thereof, respectively and the third transmission line provides fifth and sixth ports at first and second ends thereof, respectively. In the illustrative embodiment, the first, second and third transmission lines are coupled to provide equal outputs at said second, fourth and sixth ports in response to an application of a signal at the first port. The first, second and third conductors may be implemented with coaxial, stripline or microstrip type transmission lines. The looser coupling is very beneficial, especially in microstrip, to obtain high power capability and a manufacturable circuit.

Abstract: A signal distributing/synthesizing apparatus includes a 4-terminal hybrid circuit, first and second antennas, a pseudo-antenna, and first to third 4-terminal switches. The 4-terminal hybrid circuit distributes the signal input to the first terminal to the second and third terminals, and synthesizes the signals input to the second and third terminals into a signal to be output to the first terminal. The first and second antennas form a radio transmission channel for an output signal from the signal 4-terminal hybrid circuit. The pseudo-antenna forms a pseudo-radio transmission channel for an output signal from the 4-terminal hybrid circuit. The first switch complementarily switches/connects a first broadcasting unit and the first antenna to the first terminal of the 4-terminal hybrid circuit and the third switch. The second switch complementarily switches/connects a second broadcasting unit and the second antenna to the second terminal of the 4-terminal hybrid circuit and the third switch.

Abstract: Microwave semiconductor variable attenuation circuit includes a coupler, two series circuits of inductors and a plurality of means having controllable resistance. Each Inductor of the series circuits has a defined inductance, where one end of the series circuit is connected to a terminal of the coupler. Each of means having controllable resistance respectively being connected to a junction point between two respective inductors of the series circuit. All of means having controllable resistance are controlled on the basis of a common signal is provided at a single terminal. By the above features provided that inductors of defined inductance between the coupler and the means having controllable resistance (e.g. a transistor or diode), the total impedance of the attenuation circuit can be properly set and a performance degradation at high frequency can be avoided.

Abstract: A varactor based phase shifter that increases phase shift range using a lower characteristic impedance between quadrature ports than is used at its input/output ports. The circuit makes use of a four port coupler arrangement that imbeds a quarter wave impedance transformation between the input port and the quadrature ports as well as between the quadrature ports and the output port. The characteristic impedance across the quadrature ports is therefore less than the characteristic impedance across the input and output ports. In one implementation, reducing a characteristic input/output impedance of 50 to a 20 ohm quadrature port impedance results in a phase shift range increase of more than 50%.

Abstract: Microwave semiconductor variable attenuation circuit includes a coupler, two series circuits of inductors and a plurality of means having controllable resistance. Each Inductor of the series circuits has a defined inductance, where one end of the series circuit is connected to a terminal of the coupler. Each of means having controllable resistance respectively being connected to a junction point between two respective inductors of the series circuit. All of means having controllable resistance are controlled on the basis of a common signal is provided at a single terminal.

Abstract: A symmetric N×N branch-line hybrid power divider/combiner has N input ports and N output ports. The divider/combiner divides received powers at each input port and transmits and combines the divided powers to the output ports. The divider/combiner includes N through transmission lines, each coupling a respective input port to a respective output port. The divider/combiner also includes N input branch transmission lines, each coupling a respective input port to a central input node and N output branch transmission lines, each coupling a respective output port to a central output node.

Abstract: A hybrid coupler (66, 67; 72, 73) has four ports and is capable of coupling radio frequency signals having a certain frequency from at least one port to at least one other port. The hybrid coupler (66, 67; 72, 73) is implemented as a differential coupler arranged to couple differential radio frequency signals. With such a hybrid coupler a power amplifying circuit can be produced which has sufficiently low ripple on the supply voltage to be integrated together with more sensitive radio circuits, and which is also insensitive to load mismatch such that an isolator can be avoided. A differential hybrid coupler allows the output current to be shared between four transistors or amplifiers, thus reducing the amplitude of the ripple. Further, the frequency of the ripple is four times the operating frequency of the circuit, which makes it much easier to filter out the ripple.

Abstract: The microwave DPDT switch according to the present invention is composed of (1) a branch line coupler having three gaps at the branch lines among two input ports and two output ports, and (2) three SPST switches locating at the three branch line gaps to transmit input signals to the output ports.

Abstract: First and second microstriplines disposed substantially in parallel to each other and coupled with each other are formed spirally in a substantially quadrangular shape with the first microstripline being disposed inside. The space between the first and second microstriplines is set at least partly wider than the space between the adjacent turns of the pair of first and second microstriplines.

Abstract: A microwave/millimeter-wave integrated circuit realizes stable oscillation by reducing time-base variation in load impedance. This IC connects an oscillator to the input terminal of a lange coupler, and connects to the isolation port of the lange coupler a terminating resistor with resistance equal to the load impedance connected to the output terminals of the lange coupler. This stabilizes load impedance to the oscillator, and reduces variation in the oscillation frequency as a result of changes in load impedance.

Abstract: A broadband high frequency device is capable of determining linear combinations of broadband high frequent signals, in particular determining a differential signal, from input signals, being applied substantially simultaneously. One embodiment is based on a plurality of broadband microwave structures, arranged such that symmetry properties can be exploited. The output signal of this differential coupler is proportional to the difference of 2 input ports. This signal is made using a hybrid structure. A pair of broadband impedances are used to scale the 2 incoming signals with 2 complex coefficients. A symmetric structure of two identical broadband directional couplers and a symmetric power combiner are used afterwards to obtain the differential signal. The high bandwidth of both the terminations, the directional couplers and the power combiner make it possible to obtain a differential coupling factor and a common mode rejection ratio which is frequency insensitive over several decades.

Abstract: An apparatus and method provide an adjustable phase and time delay to an input signal. The apparatus includes an inverting element and first and second variable capacitors. The inverting element has a first end serially coupled with the input signal and a second end. The first variable capacitor is coupled between the first end of the inverting element and first voltage. The second variable capacitor is coupled between the second end of the inverting element and a second voltage. The first and second variable capacitors are separately adjustable to controllably vary a phase shift and a delay of a reflection of the input signal. The first and second voltages may be at the same or different potentials. The input signal may be coupled to the inverting element through a directional coupler, such as a circulator.

Abstract: An apparatus for doubling the amount of power that can be safely applied to a circulator-based isolator, which is made up of an input hybrid which receives an RF signal and outputs two divided RF signals, a Y-junction circulator that receives one of the divided RF signals at one of the circulator ports and outputs it at another circulator port, an output hybrid which receives the two divided RF signals, combines them, and sends them on, the output hybrid simultaneously receiving a returned signal, dividing it, and outputting two divided returned signals, one divided returned signal going to the circulator and the other divided returned signal going directly to the input hybrid, a phase retarding circuit which takes the half of the divided returned signal that went back to the circulator and retards its phase by 180 degrees and sends it back to the circulator, where it goes to the input hybrid as well, to be recombined with the other half of the returned signal and attenuated.

Abstract: An apparatus for doubling the amount of power that can be safely applied to a circulator-based isolator, which is made up of an input hybrid which receives an RF signal and outputs two divided RF signals, a Y-junction circulator that receives one of the divided RF signals at one of the circulator ports and outputs it at another circulator port, an output hybrid which receives the two divided RF signals, combines them, and sends them on, the output hybrid simultaneously receiving a returned signal, dividing it, and outputting two divided returned signals, one divided returned signal going to the circulator and the other divided returned signal going directly to the input hybrid, a phase retarding circuit which takes the half of the divided returned signal that went back to the circulator and retards its phase by 180 degrees and sends it back to the circulator, where it goes to the input hybrid as well, to be recombined with the other half of the returned signal and attenuated.

Abstract: First and second microstriplines 2 and 3 disposed substantially in parallel to each other and coupled with each other are formed spirally in a substantially quadrangular shape with the first microstripline 2 being disposed inside. The space between the first and second microstriplines 2 and 3 at portions disposed adjacently with the same number of turns is set longer than the space between the first and second microstriplines 2 and 3 at portions disposed adjacently with different numbers of turns.

Abstract: A broadband modem hybrid transformer couples a broadband modem to a plain-old-telephone (POTs) line. The hybrid includes a full bridge having an impedance matching network to reduce the transhybrid attenuation of the hybrid. The second matching network(s) include various resistive and reactive components which together provide an impedance value selected based upon the impedance of the telephone line typically reflected into the primary windings of the transformer. The matching network increases the transhybrid attenuation of the hybrid, and thus reducing the amount of noise which couples from the modem transmit circuit to the modem receive circuit through the hybrid.

Abstract: A dual quadrature branchline in-phase power combiner and power splitter provides a low cost and symmetrical structure for combining power from two signal ports (20, 30, FIG. 1) to an output signal port (10). When used as a power splitter, the structure accepts power from a signal port and divides the power equally and in-phase between the output signal ports (20, 30). The structure can be fabricated using microstrip, stripline, or similar technology such as suspended stripline. The structure is well matched over a large bandwidth and provides high isolation between the splitter output signal ports (20, 30).

Abstract: A multi-phase coupler including a noise reduction circuit which provides two output signals which are separately shifted in phase with respect to an input radio frequency (RF) signal. The input RF signal is capacitively phase-shifted to lead the phase of an input RF signal to provide one output signal and is inductively phase-shifted to lag the phase of an input RF signal to provide a second output signal. The two phase-shifted outputs are impedance matched to the dual input ports of a balanced radiating structure that acts as a point source when the input ports are driven in phase quadrature.

Abstract: An antenna system for a radio communication device, in particular a hand-portable telephone, having communication circuits and to be operating by circularly-polarized radio waves. In the system (1) there is provided a radiation means, preferably helical elements (2, 3, 4), a feeding network (8) having first coupling means (9) adapted for coupling to said communication circuits and second coupling means coupled to said helical elements (2, 3, 4). The interface means includes a closed resonator means (14), which has at least a first portion associated with said first coupling means (9), and having separated at least second (11), third (12) and fourth (13) portions forming said second coupling means (11, 12, 13).

Abstract: A distributed MMIC active quadrature hybrid (10) provides in-phase (I) and quadrature-phase (Q) outputs (22, 24) over an octave bandwidth. The quadrature hybrid includes in-phase and quadrature-phase amplifying elements (14, 12) arranged in a distributed manner. The in-phase amplifying elements (14) include FETs (42) with series inductive feedback (44) in the source path. The quadrature-phase amplifying elements (12) includes FETs (52) with series capacitive feedback (54) in the source path. The series inductive and capacitive feedback provides the phase difference between the hybrid's outputs. The FETs of the in-phase and quadrature-phase amplifying elements have differing gate peripheries to provide amplitude tracking over the bandwidth.

Abstract: A balanced modulator has a pair of diodes, a plurality of line patterns including a balance-to-unbalance converter, the line patterns including lines extending toward and connected to the diodes, respectively, and at least a set of capacitive stubs disposed near the lines and spaced from each other by a distance of .lambda./8 (.lambda. is the wavelength at a frequency used). The capacitive stubs are connectable to the lines by bonding wires for isolation adjustments.

Abstract: An S/N enhancer is provided which can be formed to be small in size and in which impedance matching can easily be achieved. The S/N enhancer includes two magnetostatic wave elements. First to fourth transducers each in the shape of a single line are disposed on YIG thin films of the magnetostatic wave elements in parallel and spaced from one another. An input terminal is connected to one end of the first transducer. An attenuator is connected between the other end of the first transducer and one end of the third transducer. A 180.degree. shifter and another attenuator are connected in series between one end of the second transducer and one end of the fourth transducer. An output terminal is connected to the other end of the fourth transducer. The other ends of the second and third transducers are respectively grounded.

Abstract: The present invention discloses an integrated circuit (IC) 200 including a plurality of microstrip conductive lines, i.e., 210, 220, 230, and 240. The IC includes a phase shifting means wherein the plurality of microstrip conductive lines, i.e., 210, 220, 230, and 240, may have different or equal lengths forming a coplanar phase-shifting assembly for shifting phase of the electromagnetic wave transmitted therein. The conductive lines, i.e., 210, 220, 230, and 240, are configured substantially rectangular in shape. The IC 200 also includes a decoupling means 280 for substantially decoupling and reducing the interference between the electromagnetic fields of the conductive lines, i.e., 210, 220, 230, and 240. The decoupling means 280 is a conductive means disposed inside the rectangular shape surrounded by the four conductive lines, i.e., 210, 220, 230, and 240, of the phase-shifting assembly. The decoupling means 280 and the microstrip conductive lines, i.e.

Abstract: Input is applied to a two-partition circuit that substantially equally distributes input power into two partitions having a phase difference of 90.degree., and the thus-distributed output is applied to a first driver that generates circularly polarized wave. The two outputs of the second driver, in which the circularly polarized waves generated from the first driver are coupled, are combined in a combining circuit. The end portion of the opening of the sealed case incorporating the first driver fits together with the end portion of the opening of the sealed case incorporating the second driver such that the two sealed cases together with the first and second drivers may rotate relative to each other around their cylindrical axis. The phase difference between the input of the two-partition circuit and the output of the combining circuit changes according to the relative angle of rotation around the cylindrical axis between first and second drivers.

Abstract: A wavegide hybrid junction includes a coupling section, a coupling hole, and an external cavity resonator. The coupling section is formed by removing by a predetermined length part of a common narrow side wall for isolating two rectangular waveguides. The coupling hole is formed in the upper wall of a waveguide so as to communicate with the coupling section. The external cavity resonator externally cover the coupling hole.

Abstract: An amplitude and phase cancellation circuit for modifying or reducing the phase and amplitude of a signal includes a quadrature hybrid having four ports. A first port receives an input signal and a fourth port outputs an output signal derived from the input signal. The remaining two ports are connected to circuit sections having tuneable and adjustable components for selectively varying the phase and amplitude of the output signal. When the output signal is combined or mixed with an external signal, the circuit allows for selective adjustment or cancellation of components of the external signal by generating an output signal having a phase angle opposite to and amplitude equal to the external signal components for which cancellation is desired.

Abstract: A combiner/divider is provided which includes a common output/input port and a plurality of N input/output ports and a plurality of N isolation ports. A 90.degree. phase shifter interconnects each of the N input/output ports with the common port. N transmission line balun transformers are provided with each interconnecting an input/output port with one of the N isolation ports. Each balun transformer serves as a two-way power splitter.

Abstract: A four-port transmission line device that processes two incoming RF signals of arbitrary phase and amplitude to output two corresponding RF signals of equal phase and amplitude. Two sets each of two quarter-wave transmission line segments are connected in series between corresponding input and output ports. A short circuit interconnect shorts together the junctions of the two series connected line segments. A resistive element is connected across the two input ports, and another resistive element is connected across the two output ports. The short circuit interconnection forces the combination of the two input signals into one resultant signal at the short circuited junction. Out-of-phase components of the resultant signal are absorbed in the resistor across the input ports. The remaining in-phase components are divided into two outputs signals of equal phase and amplitude.

Abstract: A control apparatus for controlling RF power supplied to first and second loads is provided. The control apparatus includes a first symmetric hybrid junction having a first port for receiving input RF power, a second port coupled to the first load and a third port coupled to a dummy load. The control apparatus further includes a second symmetric hybrid junction having a first port coupled to a fourth port of the first symmetric hybrid junction and a third port coupled to the second load. First and second variable shorts are respectively coupled to second and fourth ports of the second symmetric hybrid junction. RF power reflected by the first and second variable shorts is controllably directed through the second symmetric hybrid junction to the second load. The amplitude and phase of the RF power supplied to the second load can be controlled independently.

Abstract: The present invention has an object to provide a compact quadrature modulator manufactured at low cost in such a manner that an input level is low over a wide high frequency band, and few input signals are wrapped around an output terminal. The quadrature modulator is mainly constructed of a multi-layer substrate into which a 90-degree phase shifter is assembled, a semiconductor integrated modulator circuit into which two sets of 2-phase modulators and an output signal in-phase synthesizing circuit, and a lid. The multi-layer substrate is constructed of "n" pieces of layers in total, namely from a first substrate corresponding to an uppermost layer to an n-th substrate corresponding to a lowermost layer. The first substrate layer is a layer for assembling a semiconductor integrated circuit, or a layer for connecting a substrate with a semiconductor integrated circuit. The 90-degree phase shifter is constituted by distributed coupling circuits having wavelengths of .lambda.

Abstract: A communications station (10) couples a bidirectional input-output signal path (16') to two unidirectional signal paths; a transmit signal path (12') and a receive signal path (14'), using a controllable hybrid (20). A feedback control system in the station minimizes the amount of transmit signal appearing at the receive output port (24) of the hybrid (20). The control system spreads the spectrum of a pilot signal (40) by means of a biphase modulator (46) and a pseudorandom generator (42) to produce a spread-spectrum pilot, which is added, in a summer 30, to the transmit signal. The spread-spectrum pilot signal covers the bandwidth of the information signal, and is reflected in an amount and with a phase which depends upon the relative impedance presented to the hybrid (20) by the bidirectional signal path (16').

Abstract: A thick film balanced line multilayered structure having a substrate base of nominal 0.025 or 0.030 inch thick ceramic material, a first metal layer deposited on the substrate base, a nominal 0.003 inch thick dielectric layer deposited over and around the first metal layer, and a second metal layer deposited on top of the dielectric layer in alignment with, and parallel to, the first metal layer. The structure defines a standard circuit cell suitable for use as a balun, a capacitor or an autotransformer, for use in microwave mixers, power splitters, filters, resonators and other microwave devices. The impedance of the cell is controlled by the width of the metal layers, and ranges from 5 ohms to 125 ohms, and the frequency of the cell is controlled by the length of the metal layers.

Abstract: A stripline or microstrip feed system distributes electromagnetic power among a set of utilization devices such as the radiators of an array antenna. In the feed system, elongated assemblies of microwave couplers are arranged side by side to provide for a two-dimensional array of couplers corresponding to a two-dimensional array of radiators in rows and columns of an array antenna, and allowing beam steering in a direction perpendicular to the rows. In each assembly of couplers, different forms of couplers are employed to provide both an amplitude taper and a phase taper to the radiations of the respective radiators in each row of radiators. The couplers include the Wilkinson coupler, the hybrid coupler, and the backward wave coupler which serve as power dividers during transmission.

Abstract: A 90.degree. coupling circuit cascaded with a pair of hybrid mode latchable phase shifters provides polarization agility for an RF radiator module of the type typically used in a phased array. For example, such radiator modules typically may utilize an active microwave integrated circuit (MIC), a monolithic microwave integrated circuit (MMIC) or a passive reciprocal hybrid mode element (RHYME) circuit. These circuits are arranged to provide duplex RF transmit/receive functions with controllable phase shifts at each radiator site in a phased array. By appropriately setting the two controllable phase shifters to different combinations of phase shifts (e.g., 0.degree. and/or 90.degree.) to a dual orthogonal mode radiator, different spatial polarizations for RF radiator transmit/receive functions can be defined. The radiator itself may include a square or circular waveguide including, in some cases, a reciprocal dielectric quarter-wave plate and a non-reciprocal ferrite quarter-wave plate.

Abstract: A zero-dB hybrid or directional coupler includes a first through waveguide extending between first and third ports and a second through waveguide, parallel to the first waveguide, and extending between second and fourth ports. A plurality of branch waveguides extend between the first and second through waveguides, and are adjusted to couple signal from the first port only to the fourth port, and from the second port only to the third port (within in limits of systems isolation). Particular normalized branch line impedances provide best operation. A communication system especially adapted for use as a spacecraft uses a zero-dB coupler in a "planar" waveguide system to transpose or "crossover" the positions of two system ports, whereby the physical positions of the various ports are arranged in the same relation as their phase progression.

Abstract: There is disclosed a six-port hybrid microwave coupler comprising three inputs and three outputs which are isolated from each other and matched such that a signal applied to any one of the inputs produces signals on all three of the outputs, said signals being orthogonally distributed in phase and uniformly distributed in amplitude. The coupler has a plane configuration of transmission lines with an inner ring comprising three similar segments with the interconnection points of the segments constituting three input or outlet first ports of the coupler. The coupler also has an outer ring comprising three similar segments with the interconnection points of the segments constituting three outlet or input second ports, respectively, of the coupler. The coupler also has three radial branches connecting the interconnection points of the inner ring segments to corresponding interconnection points of the outer ring.

Abstract: Disclosed is an energy coupling device which can be used with metrical and decimetrical waves. To distribute, equipotentially and in equiphase, towards n users, the energy coming from m equipotential sources in equiphase, a 90-degree of 3 dB hybrid circuit is connected at the output of each source. This circuit distributes the power equally and with a 90-degree, aperiodic phase shift, towards two equipotential distributors in equiphase, with m inputs and n outputs, having one and the same input/output phase shift. The two distributors are connected, respectively, to the two ports of a pair of conjugated ports of n 90-degree 3 dB hybrid circuits. The powers recombined in these n circuits are respectively delivered to n users.

Abstract: A hybrid circuit module having first and second pairs of input terminals and four output terminals. First, second, third and fourth baluns each include first and second transmission line wires. The baluns are configured between the input and output terminals to isolate sources when placed across pairs of input and output terminals. An antenna system is formed with the hybrid circuit module and a plurality of radiators. The circuit module may be configured to simultaneously generate or receive two or more independent radiation patterns. A method is provided for feeding a multiarm antenna structure with a hybrid circuit network. The method includes the steps of symmetrically positioning a conductive element with respect to all of the arms, and coupling terminals of the antenna arms to the network through a conductive element. Alternately the second terminals may be electromagnetically coupled to the network without requiring the conductive element.

Abstract: A planar interdigitated microstrip coupler comprises a plurality of adjacently disposed transmission lines being spaced such that the transmission lines gradually diverge from a close spacing to a wider spacing. The planar interdigitated microstrip coupler provides equal power split and either 0.degree. or 180.degree. differential phase shift over a multi-octave bandwidth. Further, the interdigitated coupler, when used as a power combiner, provides increased cancellation of second order intermodulation products normally generated by non-linear devices, such as amplifiers, which may be fed to the inputs of the coupler. This increase in second harmonic cancellation, known for distorting signal fidelity, is particularly useful for monolithic circuit applications using amplifiers and mixers.

Abstract: A filter system which may be configured either as a stopband (notch) or passband filter having controlled gain and low ripple throughout its stopband or passband. The system includes a filter network which is operative for splitting an input signal spectrum into a pair of complimentary spectrum components and a coupler for proportionately combining these spectrum components in accordance with a prescribed gain factor. The filter network may either comprise a pair of complimentary band reject and band pass filters connected to a common input terminal or a diplexer including identical filters coupled between a splitter and a combiner.

Abstract: Disclosed is a circuit for switching a microwave output signal over to a first or a second output. The circuit has: two amplifiers receiving, at input, two parts, substantially equal in power, of an input signal, a coupler having two inputs connected to the outputs of the amplifiers and two outputs forming the outputs of the switching circuit, controllable phase-shifting means to place the signals injected at input of the coupler in phase or in phase opposition and to obtain the output signal sometimes at one output of the coupler and sometimes at the other output. The device can be applied to antenna switching circuits.

Abstract: An optically phased conformal antenna and photonic interconnect therefor that may be used in such microwave systems. Rows of microwave circuits are disposed on top of a cooling arrangement disposed on a curved surface. An optical ribbon cable disposed on top of the microwave circuits is employed to couple signals to the microwave circuits. Microwave antennas are disposed on top of the optical ribbon cable which has windows therein that permit welding of the antennas to the appropriate microwave circuits. Optical coupling of signals from the optical cable to the microwave circuits is achieved through the use of diffraction gratings, and the like, formed in the optical cable, in conjunction with laser diodes and detectors disposed on the chips.

Abstract: A low loss reflection-type analog phase shifter circuit producing a large range (nearly 360.degree.) of phase shift at X-band while achieving low attenuation (insertion loss) and little amplitude variation over all phase states. The results are achieved, in part, by using a terminating impedance which includes parallel-connected hyperabrupt varactor diodes. The circuit is implemented readily in a monolithic microwave integrated circuit using GaAs.

Abstract: A mode coupler for monopulse applications in an antenna feed system which is used for obtaining angle deviations in azimuth and elevation, and which has a main wave guide in which a plurality of electromagnetic wave modes can be propagated. The mode coupler also has a plurality of mode-selective in/out coupling ports which are all formed as simple standard wave guides mounted on the main wave guide, and in which only the H.sub.10 mode is propagatable. A separator plate is disposed in the main wave guide to convert the (H.sub.11 +E.sub.11) mode into two phase-opposed wave guide waves and, via a coupling loop, to couple them into a second wave guide mounted laterally on the main wave guide. The front edge of the separator plate forms a reflector for the H.sub.01 mode, and the reflected HO.sub.1 wave is coupled out of the main wave guide by a pair of wave guides mounted symmetrically on the main wave guide and connected via an H-plane junction to a common output wave guide.

Abstract: An improved radio frequency (RF) coupler for providing two or more secondary signals from a primary RF signal. The RF coupler has a primary coupling element and two or more secondary coupling elements for providing the two or more secondary signals. The secondary RF coupling elements are offset and nonoverlapping with respect to one another along the axis of the primary coupling element so as to reduce the cross coupling and interference between the secondary elements. The offset relationship between secondary coupling elements allows for optimal design control over the coupling between each secondary coupling element and the primary coupling element. In one embodiment, the spatial area required for the coupling elements is reduced by introducing U-shaped portions in the primary coupling element and at least one of the secondary coupling elements. In another embodiment, the secondary coupling elements are provided on separate substrates to further reduce cross interference.