Abstract: A coupler assembly may include first and second electromagnetic couplers connected together. In some examples, the couplers may be connected in cascade configuration, with at least the second coupler including at least third and fourth couplers connected in tandem configuration. In some examples, a first asymmetric coupler may include a plurality of coupler sections connected in cascade configuration, and a second coupler connected to the first coupler in tandem configuration. In some examples, a direct port of a first coupler section may be conductively connected through a second coupler section to an isolated port of the first coupler section.

Abstract: A 90° hybrid for splitting or interconnecting radio frequency power includes four gate connections, capacitances and inductances for electric capacitive coupling and magnetic inductive coupling, an arrangement of strip conductors that are disposed approximately parallel to each other and whose ends form gate connections, and whose dimensions and mutual separations are dimensioned to form the electric capacitive and magnetic inductive couplings of the 90° hybrid, and a ferrite ring surrounding the strip conductors to increase the inductive coupling.

Abstract: A wide bandwidth coupler has two outer elements around a center element. The outer elements are rectangular at their outside portions and each have a tapered nose portion next to the center element. A matching network electrically connects the two outer elements and the center element. The center element is connected to a first portion of a signal feed structure, while one of the outer elements connects to a second portion of a signal feed structure.

Abstract: In a quadrature hybrid circuit which has first and second two-port circuits 11 and 12 inserted between I/O ports P1 and P2 and between I/O ports P4 and P3, respectively, and third and fourth two-port circuits inserted between I/O ports P1 and P4 and between I/O ports P2 and P3, respectively, and which is configured so that under the condition that the I/O ports P1 to P4 are matched, a high-frequency signal fed via the I/O port P1 is divided between the I/O ports P2 and P3 and the divided two signals are output 90° out of phase with each other but no signal is provided to the I/O ports P4, there are provided SPST switches 7 and 8 responsive to external control to control electromagnetic connections or coupling across a plane of symmetry 5 of the quadrature hybrid circuit passing through intermediate points of symmetry 23 and 24 of the third and fourth two-port circuits 21 and 22.

Abstract: A circuit assembly may include one or more coupler sections, and may include a phase inverter and/or a phase shifter. A coupler section may include a phase inverter. A coupler may include first and second mutually coupled spirals disposed on opposite sides of a dielectric substrate. Conductors forming the spirals may be opposite each other on the substrate and each spiral may include one or more portions on each side of the substrate. Some circuit assemblies may include first and second multi-port coupler sections. A phase inverter or a phase shifter may be coupled between coupler sections. In some examples, a circuit assembly may include first and second conductors each having first and second ends and mutually inductively coupled turns, and a capacitive device coupling the first ends of the first and second conductors to a reference potential.

Abstract: An improved analog front end and methods for increasing the power efficiency of duplex signals on a transmission line are disclosed. The improved analog front end bifurcates a hybrid into a fixed portion and an adaptive portion. The adaptive portion combines a biquad and a summer to produce a filter transfer function suited to compensate for transmission line irregularities. A method for configuring a local transceiver to minimize power requirements at a remote transmitter is disclosed. Broadly the method entails, applying a transmit signal to a front end in the absence of a remote signal; optimizing the transmit signal power; recording the reflected transmit signal; applying an adaptive filter in response to transmission line irregularities; and controllably adjusting the adaptive filter to minimize the amplitude of the reflected version of the transmit signal in the receive path. A method for recovering a remotely generated signal is also disclosed.

Abstract: A non-radiative dielectric (NRD) waveguide modulator is provided having a waveguide type hybrid coupler, in which by forming a waveguide type 180° hybrid coupler and waveguide as a single body, the structure is simplified and manufacturing processes are reduced. The NRD waveguide modulator includes a conducting housing having a lower conducting plate and an upper conducting plate; a hybrid coupler which is processed in the form of conduit lines inside the conducting housing and includes a ring portion and a plurality of waveguides extended from the ring portion in the radial direction, in modulator, and a termination which is connected to an isolation port that is an end of any one waveguide of the hybrid coupler and terminates a signal reflected by the modulator by consuming the signal internally.

Abstract: A rat race circuit has an annular transmission line formed on a microstrip dielectric substrate. A terminal for port 1 is formed at any given position of the annular transmission line. Respective terminals for port 2 and port 3 are formed at respective positions distant from the position of port 1 in the counter-clockwise and clockwise directions each by a distance of ?g/4 (?g: effective wavelength). Moreover, at the position distant from the position of port 2 in the counter-clockwise direction by the distance of ?g/4, a terminator resistor (R=50?) is formed. A local oscillator signal is supplied to port 1, and first and second mixer inputs are connected respectively to port 2 and port 3. The local oscillator signal divider and a low noise converter using the divider are thus provided that are scarcely influenced by matching with respect to mixers and provide stable performance and high isolation.

Abstract: A class of modular, double-sided, edge-mounted printed circuit (PC) board modules and an associated modular network architecture for constructing stripline signal processing networks including high-power analog amplifiers and beam forming networks for driving multi-beam antenna systems. The stripline signal processing networks are characterized by network elements constructed from defined-length segments of transmission media configured to exhibit precisely determined phase and impedance characteristics. These circuits may also include conventional passive “lumped” electrical elements, such as resistors, capacitors and inductors; non-linear circuit elements such as diodes; and active electrical elements, such as amplifiers and transistors.

Abstract: A microwave coupler is constructed in a multilayer, vertically-connected stripline architecture provided in the form of a microwave integrated circuit that has a homogeneous, multilayer structure. Such a coupler has a vertically-connected stripline structure in which multiple sets of stripline layers are separated by interstitial groundplanes, and wherein more than one set of layers has a segment of coupled stripline. A typical implementation operates at frequencies from approximately 0.5 to 6 GHz, although other frequencies are achievable.

Abstract: An apparatus directs two high-power UHF transmitter signals to one or the other or a combination of output destinations as determined by the setting of control components. Redirection between outputs can be performed continuously under full power. Using the apparatus, synchronous amplifiers directed to the same output produce a signal with all of the power of both amplifiers. The signals can be shifted to the station load without shutting down the amplifiers. After a failure, the remaining amplifier can be redirected to provide a clean signal.

Abstract: The invention relates to a power management arrangement which comprises, formed as a multilayer structure (100), several insulating layers (130, 132, 134, 136); several conductive layers (124, 126, 128) functioning as reference planes; a first port (101), a second port (102) and a third port (104); a first transmission line (106) from the first port (101) to the second port (102), a second transmission line (108) from the first port (101) to the third port (104); means (110, 112, 114, 122) for connecting the transmission lines (106, 108) to the ports (101, 102, 104); and at least one passive element (116) between the second and the third port (102, 104). In the presented power management arrangement, the first transmission line (106) is in an insulating layer (130, 132, 134, 136) other than the one where the second transmission line (108) is.

Abstract: A four port hybrid microstrip circuit of modified Lange type, comprising a microstrip pattern including a first strip conductor between an input port (P1) and a direct port (P2) and a second strip conductor between an isolated port (P3) and a coupled port (P4). These two conductors are divided into parallel sections being mutually interdigitated and divided ibnto two parts (10,20) located side by side to each other.

Abstract: An apparatus directs two high-power UHF transmitter signals to one or the other or a combination of output destinations as determined by the setting of control components. Redirection between outputs can be performed continuously under full power. Using the apparatus, synchronous amplifiers directed to the same output produce a signal with all of the power of both amplifiers. The signals can be shifted to the station load without shutting down the amplifiers. After a failure, the remaining amplifier can be redirected to provide a clean signal.

Abstract: A phase control mechanism for broadcast RF transmission using pairs of transmission lines feeding a dual port antenna continuously monitors phase error between either the signals carried by the two lines or the physical heights of the bottom elbows where the two lines turn upward to ascend a tower. The mechanism minimizes phase error by altering the propagation time in one or both lines. Causes for such phase errors include climatic conditions such as unmatched heating by sunlight and cooling by wind. Effects of such phase errors include beam tilt and reduction in effective broadcasting range. Systems for which such phase control is applicable include broadband transmission systems carrying one or more channels of television and radiating them using a single antenna on a tower.

Abstract: A microwave frequency device includes: a first substrate having a dielectric layer and a conductive film disposed on opposing first and second sides of the dielectric layer, the conductive film on the first side of the dielectric layer of the first substrate including at least one signal line; and a second substrate having a dielectric layer, conductive film disposed on at least one of first and second opposing sides of the dielectric layer, and at least one cut-out where the dielectric layer and conductive film have been removed, wherein the first and second substrates are bonded together to form a bonded assembly such that (i) a portion of the signal line of the first substrate is sandwiched between the dielectric layers of the first and second substrates, and (ii) the at least one cut-out exposes a portion of the signal line, thereby forming a microstrip portion. A method of forming same is also disclosed.

Abstract: Switchable path length coupler/dividers. Coupler/divider operation over multiple frequency bands is provided by using switchable path lengths. In one implementation, a Wilkinson-style device with switches to select different path lengths and therefore operating frequencies. In a rat-race style device, switches select races of different lengths, and therefore operating frequencies.

Abstract: In accordance with the present invention, a quadrature hybrid circuit is provided comprising a first spiral inductor and a second spiral inductor separated by an insulating layer to provide all necessary capacitances intrinsically. Further, a vector modulator circuit is provided that incorporates a plurality of quadrature hybrid circuits on a MMIC contained within a chip scale package.

Abstract: Methods and apparatus are provided for substantially reducing and/or canceling nonlinearities of any order in circuits, devices, and systems such as amplifiers and mixers. In particular, methods and apparatus are provided for substantially reducing and/or canceling third order nonlinearities in circuits, devices, and systems such as amplifiers and mixers. A first coupler is used to split an input signal into two equal-amplitude in-phase components, each component is processed by two nonlinear devices with different nonlinearities, and a final combiner, such as a 180-degree hybrid, recombines the processed signals 180 degrees out of phase and substantially reduces and/or cancels the undesired nonlinear distortion components arising due to nonlinearities in the nonlinear devices.

Abstract: A system for providing independent or co-spatial antenna patterns for independent inputs from a basestation comprises a phased-array antenna having a plurality of antenna columns radiating generally redundant antenna beam patterns. The array employs a feed network for feeding the antenna elements of the array. The feed network receives a plurality of independent inputs. Each of the inputs is split to feed specific ones of the antenna elements and to be combined and correspondingly weighted for output to a shared plurality of the antenna elements of the array. In one embodiment this combining and weighting is carried out by at least one hybrid matrix combiner. The weighting may include adjusting amplitudes and phases of the outputs by the combiner.

Abstract: A variable power divider and method can vary the RF power between ports in a high power and multi-carrier RF environment, such as is used in controlling signals sent and received in a base station antenna. The variable power divider can include a single-control phase shifter and a hybrid power divider. The single-control phase shifter can comprise a three-port device having a single input port and two output ports. The single-control phase shifter can further comprise a variable adjuster that can change or adjust the phase between two RF signals. The hybrid power divider can comprise a four-port device having two input ports and two output ports. Both the single-control phase shifter and the hybrid power divider can comprise substantially planar structures that are suitable for high-speed manufacturing. The output ports of the hybrid power divider can be coupled to various devices such antennas or power absorbing elements.

Abstract: A coupling device defined by an RF circuit board having a cavity formed therein and a plurality of conductive traces and a ground plane, a coupler board having opposites sides and conductive traces, and first and, second metal shields. When assembled, the coupler board is supported by the RF circuit board, and cavities are formed on opposite sides of the coupler board by the first and second metal shields.

Abstract: RF and microwave radiation directing or controlling components are provided that may be monolithic, that may be formed from a plurality of electrodeposition operations and/or from a plurality of deposited layers of material, that may include switches, inductors, antennae, transmission lines, filters, hybrid couplers, antenna arrays and/or other active or passive components. Components may include non-radiation-entry and non-radiation-exit channels that are useful in separating sacrificial materials from structural materials. Preferred formation processes use electrochemical fabrication techniques (e.g. including selective depositions, bulk depositions, etching operations and planarization operations) and post-deposition processes (e.g. selective etching operations and/or back filling operations).

Abstract: Two fixed-phase-related signals of arbitrary (unequal) magnitude are combined without incurring combining loss by use of a signal reflection technique wherein the higher magnitude signal is phase-synchronously reinforced along its path through the combining system. In a specific embodiment, two signal sources are fed as equal phase signals through respective counter-rotating circulators to a four-port first combiner, wherein the first output port of the combiner is provided with a one-eighth wavelength phase delay to a termination and the second output port is directly terminated, so that reflected signals as seen at both input ports return exactly in phase and of equal magnitude to one another. Thereupon the reflected signals are directed by the respective circulators as phase-synchronized signals to a second combiner which combines the phase synchronized signals into a common output signal. The resultant output is the sum of the inputs irrespective of relative magnitudes of the inputs.

Abstract: A circuit for processing radio frequency signals. The circuit includes a substrate where the circuit can be placed. The substrate can be a meta-material and can incorporate at least one dielectric layer. A four port circuit and at least one ground can be coupled to the substrate. The dielectric layer can include a first region with a first set of substrate properties and a second region with a second set of substrate properties. Substrate properties can include permittivity and permeability. A substantial portion of the four port circuit can be coupled to the second region. The permittivity and/or permeability of the second region can be higher than the permittivity and/or permeability of the first region. The increased permittivities and/or permeabilities can reduce a size of the four port circuit and effect a change in a variety of electrical characteristics associated with the four port circuit.

Abstract: A coupler of distributed type comprising a first conductive line carrying a main signal between two end terminals, a second conductive line coupled to the first one and between two terminals of which flows a sampled signal, proportional to the main signal, and two capacitors respectively connecting the two terminals of each of the lines.

Abstract: The invention relates to a 90° power divider for distributing the power of an input signal (E) to two output branches (A1, A2) that are phase-shifted against each other by 90°. A capacity (C) is arranged in one output branch (A1) and an inductivity (L) is arranged in the remaining output branch (A2). Said capacity and inductivity are measured as follows: C=½*&pgr;*Z1*Fo, L=Z2/2*&pgr;*Fo, whereby Fo is the centre frequency and Z1 and Z2 are the terminating resistances of the output branches (A1, A2) respectively.

Abstract: A variable power divider and method can vary the RF power between ports in a high power and multi-carrier RF environment, such as is used in controlling signals sent and received in a base station antenna. The variable power divider can include a single-control phase shifter and a hybrid power divider. The single-control phase shifter can comprise a three-port device having a single input port and two output ports. The single-control phase shifter can further comprise a variable adjuster that can change or adjust the phase between two RF signals. The hybrid power divider can comprise a four-port device having two input ports and two output ports. Both the single-control phase shifter and the hybrid power divider can comprise substantially planar structures that are suitable for high-speed manufacturing. The output ports of the hybrid power divider can be coupled to various devices such antennas or power absorbing elements.

Abstract: A line driver for coupling a data transceiver to a transmission line having a load impedance via a transformer with a turns ratio of 1:n includes an input port for receiving an input signal voltage from the data transceiver, an output port for supplying an output signal voltage to the transformer, and an amplifier circuit for amplifying the input signal voltage. The amplifier circuit includes a first output stage, a second output stage coupled to the output port, an output resistor coupled to the first output stage, a feedback path from the first output stage to an input of the amplifier circuit, and a line matching network coupled between the first output stage and the second output stage, for compensating variations in the load impedance, so that a synthesized output impedance of the line driver substantially matches an actual load impedance Z of the transmission line.

Abstract: A linear metamaterial comprises a transmission line, having a linear dimension, and is loaded with capacitors, and shunted with an inductor such that for an electromagnetic wave, having a wavelength greater than the linear dimension and traveling along the axis of the transmission line, the effective permeability and permittivity of the metamaterial are simultaneously negative. Applications for the metameterial are also disclosed.

Abstract: A four port hybrid microstrip circuit of modified Lange type, comprising a microstrip pattern including a first strip conductor between an input port (P1) and a direct port (P2) and a second strip conductor between an isolated port (P3) and a coupled port (P4). These two conductors are divided into parallel sections being mutually interdigitated and divided ibnto two parts (10,20) located side by side to each other.

Abstract: A balancing/unbalancing (balun) structure for operating at frequency f1 includes a microstrip printed circuit board (PCB). A balun on the PCB includes two input ports are coupled to a differential signal. An isolated port is connected to ground through a matched resistance. An output port is coupled to a single-ended signal corresponding to the differential signal. A plurality of traces on the PCB connect the two input ports, the load connection port and a tap point to the output port. A f2 rejection filter on the PCB is wrapped around the balun and includes a first folded element with a transmission length of &lgr;2/4 and connected to the output port. A second folded element has a transmission length of &lgr;2/4 and connected to the tap point. A third folded element connects the tap point to the output port and has a transmission length of &lgr;2/4.

Abstract: A VCO having an automatic amplitude control circuit in the form of a sensing amplifier provided in the feedback loop to sense the oscillator amplitude and draw current away only when the positive peak voltage is above a certain value. In general, any amplifier may be used in the feedback loop that outputs current proportional to a peak positive input (in a non-linear and asymmetric fashion with respect to the changing voltage). In one example, the amplifier in the feedback loop comprises first and second transistors that are set nominally in cut off and behave as class C amplifiers. The advantage of this amplifier transistor configuration is that the amplifier they form has a low load on the LC tank circuit and a high input impedance.

Abstract: An RF signals amplification block receives a first RF signal (RFin), and comprises means of amplification (3, 4, 12, 15) of this first RF signal so as to deliver a second, amplified, RF signal (RF1). This signal (RF1) must be amplified by a predetermined nominal power (Pout) so as to be delivered at the output of the block.

Abstract: A circuit for processing radio frequency signals. The circuit includes a substrate where the circuit can be placed. The substrate can be a meta-material and can incorporate at least one dielectric layer. A four port circuit and at least one ground can be coupled to the substrate. The dielectric layer can include a first region with a first set of substrate properties and a second region with a second set of substrate properties. Substrate properties can include permittivity and permeability. A substantial portion of the four port circuit can be coupled to the second region. The permittivity and/or permeability of the second region can be higher than the permittivity and/or permeability of the first region. The increased permittivities and/or permeabilities can reduce a size of the four port circuit and effect a change in a variety of electrical characteristics associated with the four port circuit.

Abstract: A highly efficient power amplifier is composed of (1) two microwave divide/through switches, (2) two power amplifiers, connected with the two microwave divide/through switches, to amplify the signal power transmitted from the first microwave divide/through switch, and (3) a half-wavelength transformer, connected to an output terminal of one of the power amplifiers, to delay the phase of the amplified signal by a half-wavelength.

Abstract: An antenna feed system comprises a single horn having corrugations and four evenly spaced waveguide ports on sides of a single one of the corrugations. A combiner network receives signals at approximately 20 GHz from the four waveguide ports and outputs sum and difference output signals. A transducer provides transmit signals at approximately 30 GHz and approximately 44 GHz to a rear end of the single horn.

Abstract: The present invention relates to a four port hybrid comprising a first set (10) of N coupled transmission lines (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I) and a second set (20) of N coupled transmission lines (20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I) where N≧4. Said coupled transmission lines in said first set (10) are electrically connected to said coupled transmission lines in said second set (20) to form a first spiral shaped electrical conductive path, a second spiral shaped electrical conductive path and N−1 electrically isolated transposition portions (30, 40, 50, 60, 70, 80, 90, 110) of said first and second spiral shaped electrical conductive paths. A first end of the first spiral being an input port (P1). A first end of the second spiral being a port (P4) connectable to ground. A second end of the first spiral being a first output port (P3) and a second end of the second spiral being a second output port (P2).

Abstract: A microwave coupler has a planar form with a transmission line segment oriented at an angle relative to a main transmission line. The planar form of the transmission line, such as in a printed circuit board, helps reduce the size and manufacturing costs for the coupler. When placed a prescribed distance from the main transmission line and oriented at an appropriate angle, the directivity and coupling factor requirements can be met precisely with minimal tuning. Where fine tuning is required, a tuning screw and resistor disposed adjacent to the transmission line segment are provided.

Abstract: An in-band group delay equalizer is formed in a simple circuit configuration so as to have a flat group delay characteristic over a wide frequency band without having a peak of group delay near each passband edge. The in-band group delay equalizer includes a plurality of convex group delay circuits. Each convex group delay circuit is formed of one hybrid coupler and two resonators connected to respective divided output ports of the hybrid coupler. The center frequencies of the respective convex group delay circuits are set to be different from each other so that the overall group delay characteristic of the in-band group delay equalizer becomes flat. The bandwidth and the group delay can be easily adjusted.

Abstract: Disclosed is a dual band coupler, in which a dielectric layer having a coupling signal line is positioned between dielectric layers having a first main signal line and a second main signal line. Coupling coefficients of first and second signal lines can be independently controlled by laminating different numbers of dielectric layers between the coupling signal line and main signal lines, respectively. A shielding pattern for excluding mutual electromagnetic interference between the first and second main signal lines is formed on the dielectric layer having the coupling signal line to improve an isolation, and a small sized-dual band coupler can be provided because the dielectric layer having a ground pattern can be omitted.

Abstract: A high-power coupler formed from a substrate, such as a dielectric printed circuit board, is disclosed. The through arm and coupled arm(s) of the coupler have a conductor plated on the top, bottom and edges of the dielectric printed circuit board, completely enclosing the dielectric material in the conductor. A metal package surrounding the coupler forms the outer ground. Thin non-conductive struts of the dielectric material of the printed circuit board interconnect the separate arms of the coupler. The coupler may be integrated with microstrip circuitry, such as switches and resistors.

Abstract: A high-power coupler formed from a substrate, such as a dielectric printed circuit board, is disclosed. The through arm and coupled arm(s) of the coupler have a conductor plated on the top, bottom and edges of the dielectric printed circuit board, completely enclosing the dielectric material in the conductor. A metal package surrounding the coupler forms the outer ground. Thin non-conductive struts of the dielectric material of the printed circuit board interconnect the separate arms of the coupler. The coupler may be integrated with microstrip circuitry, such as switches and resistors.

Abstract: The present invention relates to a method of shortening a microwave circuit and a printed circuit board made by using the method. The effective dielectric constant of the dielectric material of the microwave circuit may be increased, thereby efficiently achieving the purpose of shortening the size of the microwave circuit, thereby increasing the usage of the area of the circuit board, and thereby reducing production of noise.

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 circuit for the variable attenuation of microwave signals including at least a first coupler and a first series circuit of inductors. Each inductor has a defined inductance, and one end of the first series circuit is connected to a first terminal of the first coupler. Also included is a second series circuit of inductors, each inductor having a defined inductance, where one end of the second series circuit is connected to a second terminal of the first coupler. A plurality of controllable resistance mechanisms, each being connected to a junction point between two respective inductors of the first or second series circuit are also included. The other end of the first series circuit is grounded through a first termination resistor and the other end of the second series circuit is grounded through a second termination resistor.

Abstract: A microwave coupler has a planar form with a transmission line segment oriented at an angle relative to a main transmission line. The planar form of the transmission line, such as in a printed circuit board, helps reduce the size and manufacturing costs for the coupler. When placed a prescribed distance from the main transmission line and oriented at an appropriate angle, the directivity and coupling factor requirements can be met precisely with minimal tuning. Where fine tuning is required, a tuning screw and resistor disposed adjacent to the transmission line segment are provided.

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 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.