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: A waveguide directional filter for combining multiple high power UHF television broadcasting transmitters on to a common antenna. The directional filter arrangement includes an input waveguide, an output waveguide and an interconnected cascade assembly of two or more cavity resonators. The input and output waveguides are each aperture-coupled to an end cavity resonator of the cascade assembly. The edges of each aperture incorporate inwardly extending curved protrusions of a characteristic shape. Alternatively or additionally, at least one pair of non-adjacent cavity resonators are coupled by at least one additional coupling element incorporating an external transmission line.

Abstract: An inner conductor comprising high impedance portions and low impedance portions alternately connected to each other is disposed in the center of an outer conductor having a substantially square cross-section. Two holes are formed in one side of the outer conductor so as to extend through the wall of the outer conductor. A substantially &pgr;-shaped coupling line comprising a main line portion and probe-connecting portions is formed on the surface of a dielectric substrate. Probes made of conductor rods are connected at the ends, respectively. A resistor is provided at one end of the main line of the coupling line. The other end of the main line functions as an output terminal, and can be connected to an external circuit. The probes are inserted through the holes. The dielectric substrate is disposed inside of the outer conductor at predetermined positions.

Abstract: A waveguide directional filter is described for combining multiple high power UHF television broadcasting transmitters on to a common antenna. The filter arrangement comprises an input waveguide (1) and an output waveguide (2). The waveguides are rectangular having broad walls (3) joined by narrow walls (4) whose width/height ratio is approximately 4:1. The two waveguides are connected by at least one direct-coupled cavity resonator (5). Coupling between the cavity and each waveguide is obtained by a respective characteristic aperture (7, 7a) in the form of a rectangle whose four sides have inwardly extending hemicycle sectors (8, 9, 10 and 11).

Abstract: A filter circuit filters unnecessary frequency components within a signal. The filter circuit includes a first and a second line pattern and a closed loop pattern portion. The first line pattern has two ends and one end thereof is connected to an input terminal and the other is opened or grounded. The second line pattern has two ends and one end thereof is connected to an output terminal and the other being opened or grounded. The closed loop pattern portion, which is interposed between the first and the second line pattern, has two or more closed loop patterns and each of the closed loop patterns has an electromagnetic coupling portion coupled to each of the first and the second line pattern.

Abstract: An inner conductor comprising high impedance portions and low impedance portions alternately connected to each other is disposed in the center of an outer conductor having a substantially square cross-section. Two holes are formed in one side of the outer conductor so as to extend through the wall of the outer conductor. A substantially &pgr;-shaped coupling line comprising a main line portion and probe-connecting portions is formed on the surface of a dielectric substrate. Probes made of conductor rods are connected at the ends, respectively. A resistor is provided at one end of the main line of the coupling line. The other end of the main line functions as an output terminal, and can be connected to an external circuit. The probes are inserted through the holes. The dielectric substrate is disposed inside of the outer conductor at predetermined positions.

Abstract: In a dual-mode bandpass filter, a metal film is partially formed on one surface of a dielectric substrate or at a certain vertical level within the dielectric substrate, first and second input/output coupling circuits are coupled to the metal film, at least one capacitor is loaded to the metal film so that when an input signal is applied from either input/output coupling circuit, two resonant modes generated in the metal film are coupled. The capacitor preferably includes via-hole electrodes opposing the metal film.

Abstract: An integrated component providing the function of both a conventional directional coupler and a low-pass filter having two attenuation poles at a specified frequency band without changing the line length. Stub lines are connected to both ends of a main transmission line of a directional coupler. A frequency of the attenuation poles is adjustable by characteristic impedance, terminating conditions, and line length of the stub lines.

Abstract: A low pass filter exhibiting low loss, low reflection, and Gaussian phase distortion characteristics at microwave and radio frequencies is provided. The low pass filter may comprise a negative feed forward network having a first directional coupler having a resonant frequency f.sub.0 and a second directional coupler having a resonant frequency f.sub.0, a through port of the first directional coupler being coupled to a through port of the second directional coupler, a coupled port of the first directional coupler being coupled to a coupled port of the second directional coupler, and an isolated port of the first directional coupler and an isolated port of the second directional coupler being terminated in matched loads. Additional embodiments employing multiple negative feed-forward networks are also disclosed.

Abstract: A multiplexer comprises a number of directional filters 17.sub.n connected to a transmission line feeding an antenna 2, 3. Signals to be multiplexed fed to the filters 17.sub.n may be sent via respective switches 16.sub.n. Unlike prior multiplexers where each directional filter defines a respective channel of the multiplex, the channels of the multiplexer of the invention, apart from one at the end, are defined by the band pass response of one directional filter and the band stop response of another directional filter, since the band pass responses of the directional filters from the input connected to the switch to the output connected to the transmission line, and the corresponding band stop responses between the two output ports connected to the transmission line, overlap each other. The same arrangement may be used for demultiplexing.

Abstract: A surge protection apparatus (20) has a first quadrature coupler (22) with a first input (24) coupled to an electrical ground (26), and a second input (28) connected to an input signal. A second quadrature coupler (34) having a third input (32) is coupled to a first output (30) of the first quadrature coupler (22). A fourth input (38) is coupled to a second output (36) of the first quadrature coupler (22). A third output (40) is coupled to a signal port and a fourth output (42) is coupled to the electrical ground.

Abstract: A power distributor for microwave signals has n inputs and n outputs, n/2 coupler elements, four power distributor elements each having n/2 inputs and n/2 outputs. The inputs of the first and third distributor elements correspond to respective inputs of the distributor and the outputs of the second and fourth distributor elements correspond to respective outputs of the distributor. The outputs of the first distributor element are connected to respective first inputs of the couplers and the outputs of the third distributor element are connected to respective second inputs of the couplers. The inputs of the second distributor element are connected to respective first outputs of the couplers and the inputs of the fourth distributor element are connected to respective second outputs of the couplers.

Abstract: A broadband microstrip filter structure employs a first transmission line which basically consists of a series of capacitor plates which extend between a dielectric layer from a first location to a second location and each of the series of plates are connected together with a top plate on the top surface of the dielectric and a bottom plate located a given distance beneath the dielectric layer. A second transmission line alternates between the top and bottom layers of the dielectric and consists of a second series of capacitive plates whereby each capacitor is connected to an adjacent capacitor with the top plate of the first connecting to the bottom plate of the second and the bottom plate of the first connecting to the top plate of the second and so on. This pattern is repeated so that the conductor path alternates from the top to the bottom plate. Various capacitors are selected to provide predetermined length resonators while various other capacitors are provided to provide coupling sections.

Abstract: A radio frequency multiplexer provides a desired channelization plan by directionally coupling high quality linearly polarized filters to a waveguide manifold. The multiplexer includes a waveguide manifold for transmitting signals in a plurality of different frequency channels, a polarization translating coupling aperture arrangement, a circular polarizer, and filter for each channel. Wide band signals traveling along the waveguide manifold exit the waveguide through the coupling aperture arrangement. The linearly polarized signal from the waveguide manifold translates to a circularly polarized signal through the coupling aperture arrangement and these circularly polarized signals are translated back to linearly polarized signals by the circular polarizer. The linearly polarized wide band signals from the circular polarizer are then filtered with the filter device which allows only signals in a channel to be separated to pass.

Abstract: A switchable dual mode directional filter system includes two identical filters coupled to input and output waveguides at the same plane in phase quadrature. Each waveguide has two ports through which the signal enters and exists. One of the filters has a switching device incorporated therein for selecting the desired output port. One embodiment of the switching device includes a pair of coupling members that extend radially inward within the cavity of the filter toward a central axis. These coupling members define two coupling positions for the system. Solenoids move the two coupling members into and out of the cavity of the filters. Only one coupling member is used at a given time. This switching device is designed to change the polarity of one of the components of the signal wave to change its wave characteristics in the output waveguide. As a result, the desired port of the output waveguide can be selected easily.

Abstract: A directional filter is provided implemented with passive lumped elements in several embodiments from a general 18-element network, to an intermediate ten-element embodiment and a simple two-element filter each with features and advantages depending on the application. In general, a directional filter with lumped elements requires less physical area with similar performance characteristics as conventional transmission lines which is desirable in technologies such as MMIC.

Abstract: A method and apparatus for multiplexing broad band high frequency signals comprises a microwave coupler. A first source of signals is connected to the through-arm of the coupler and a second source of signals of higher frequency is connected to the coupling arm of the coupler. By using a coupler designed for operation at the frequencies of the signals from the second source, the loss of signal strength from the second source is significantly reduced while the loss of signal strength from the first source is only slightly greater than that incurred in prior known multiplexer.

Abstract: A method and apparatus for multiplexing broad band high frequency signals using either a parallel line contra-directional microwave coupler or forward coupling microwave coupler. A first source of signals comprising multiple decades of frequencies below a first frequency is connected to the through-arm of the coupler and a second source of signals comprising a higher band of frequencies is connected to the coupling arm of the coupler. By using a coupler designed for operation at the frequencies of the signals from the second source, the loss of signal strength from the second source is significantly reduced while the loss of signal strength from the first source is only slightly greater than that incurred in prior known microwave multiplexers.

Abstract: A combined switch and filter comprising coupled first and second quarter-wave transmission line sections and switching elements for providing selective coupling and filtering between ports of the switch coupled to the ends of the quarter-wave sections.

Abstract: Apparatus for transferring RF signals between a plurality of inputs and a plurality of outputs comprises a plurality of output multiplexers 30.sub.1 . . . 30.sub.10, each made up of a plurality of hybrid/tunable filter combinations 21.sub.1 . . . 21.sub.8. The RF signal inputs of the apparatus are supplied to one output multiplexer 30.sub.1 and the inputs of each output multiplexers are connected to the inputs of the adjacent multiplexer, such that a signal not transmitted by one output multiplexer will be passed to a next output multiplexer, and so on. By appropriate tuning of the filters 24 in the output and multiplexers the RF signals may be reconfigurably distributed between the inputs and the outputs, and, the need for switching is avoided while maintaining an acceptably low path loss.

Abstract: A multiband feed system for a reflector antenna, capable of operating simultaneously at a plurality of separate bands of wide bandwidths and of having both frequency and polarization diversity, comprises a common tapered waveguide for carrying the frequency multiplexed bands and orthomode junctions spaced along the length of the waveguide for coupling signals in a single frequency band in and out of the waveguide. 90.degree. and 180.degree. narrowband polarization devices between the orthomode junctions and the orthomode transducers provide polarization diversity. A dual-depth corrugated flared horn operating in a beamwidth saturation mode with the feed system gives a radiation pattern with low cross-polarization content and nearly equalized subreflector illumination at all bands of operation.

Abstract: A directional coupler is provided which has an appropriately dimensioned principle waveguide with a frequency dependent reactive boundary interior surface such that the principle waveguide is suitable to simultaneously: (i) support, without depolarization, effective propagation of first signals in a high frequency band at a HE11 mode with greater concentration of energy near the axis of the principle waveguide than near the interior surface and no effective propagation of first signals at any unwanted mode, and (ii) support, without depolarization, effective propagation of second signals in a lower frequency band at a EH11 mode having a greater concentration of energy near the interior surface of the principle waveguide than near the axis and no effective propagation of second signals at any unwanted mode.

Abstract: A directional filter wherein dielectric resonators tuned to the operating frequency couple electric energy from port one to port four while electrical energy at other frequencies passes through the filter to port two.

Abstract: A dual adjacent directional filter is disclosed for the splitting and combining of signals. This device is composed of a six port filter wherein if the appropriate signal is entered into the center port two signals having the same frequency as the input signal and equally divided amplitudes will output to the corresponding two output ports. This device is comprised of two transmission lines being equally divided by an impedance matching transmission line. Between the impedance matching transmission line and the regular transmission lines is located a filtering device of either a loop type transmission line; resonator; or transmission stubs.

Abstract: A Beam-forming Network includes a plurality of directional couplers and phase shifters and which can interconnect both a transmitter and a receiver to the same group of radiating elements of an antenna even though the transmitter frequency band is different and well spaced from the receiver frequency band. This is accomplished, in accordance with the invention, by using directional couplers each of which has a variable response over a wide band of frequencies but which is designed so that its response over the transmitter frequency band is stable and its response over the receiver frequency band is also stable.

Abstract: An h.f. electrical network consists of a transmission line device in the form of a closed cavity having two end plates between which extend four quarter wave resonators positioned symmetrically about an axis passing through both end plates. The device is provided with four ports connected to two pairs of transmission line loops each of which couple equally into two adjacent resonators. The device exhibits frequency selective properties and can be used to couple two carrier frequencies into a common antenna while maintaining electrical isolation between the two signal sources.

Abstract: A dual Gunn self-oscillating mixer is shown which can mix signals in the range substantially without introducing any noise and with high input signal power handling capacity and with higher output mixed signal power than conventional, owing to boosted power from more than one microwave cavity. The device is comprised of two cavities and connected by a 180.degree. phase shift coax line for injection locking, or a cavity wall hole in yet another embodiment. The device handles larger power levels without burning out as compared to conventional type mixer devices such as Schottky barrier diodes having nearly 30 times the burnout susceptibility.

Abstract: A 180.degree. hybrid receptive of a fundamental frequency signal which may be adjusted over a range of frequencies produces the fundamental frequency signal at two output ports phased 180.degree. apart. Each of the output ports is coupled to a non-linear active device which produces the fundamental frequency and odd and even harmonics thereof. A 180.degree. and 0.degree. hybrid is coupled to receive at respective input ports the signal from the active devices and to produce at one output port all the odd harmonics and to produce at the other output port all of the even harmonics of the fundamental frequency. The even and odd harmonics of the fundamental frequency appearing at the two output ports of the 0.degree. and 180.degree. hybrid are isolated from one another.

Abstract: A millimeter wave suspended substrate multiplexer is disclosed which is comprised of a plurality of hybrid-filter-hybrid channel dropping sections. The components of the multiplexer are enclosed in a metallic housing forming a cavity surrounding the multiplexer components. Each of the hybrid-filter-hybrid sections is comprised of first and second 90.degree. hybrid couplers which are connected by a pair of identical bandpass filters. Spurious waveguide energy propagation modes which would otherwise be generated in the cavity surrounding the 90.degree. suspended hybrid couplers are eliminated by the use of a plurality of mode suppression pins extending between the top and bottom portions of the metallic housing and passing through the branch lines of the couplers.

Abstract: An electronically tunable band reject filter rejects only frequencies of a signal that are in the reject band around its center frequency. The band reject filter includes an input directional coupler for sampling of the signal that is to be filtered and provides a first and second signal thereby. The first signal is filtered by a bandpass filter that passes only frequencies of the signal that are around the center frequency of the bandpass filter. An output directional coupler combines the second signal with the filtered signal and obtains on a difference port the difference between the second signal and the filtered signal. The frequencies of the signal that are centered around the center frequency of the bandpass filter are thereby rejected.

Abstract: First and second directional couplers each having a primary arm, a through arm and two secondary arms with a resonant circuit constructed to include the two secondary arms of each directional coupler. The directional filter forms a four port device with signals of a first frequency being applied to the first port and coupled to the fourth port by the resonant circuit, and signals applied to the third port being conveyed directly to the first port. Signals other than those at the first frequency are not coupled between the first and fourth ports.

Abstract: A microwave device is disclosed comprising a microstrip line pattern including an open ring forming a 1/2.lambda. resonator having a narrow gap in which the electromagnetic field is closely tied to the ring.

Abstract: A microwave feed forward passive coupling system for separation of at least a first and a second signal portion into at least first and second signal components of differing frequencies. The first and second signal portions have a majority of the second and first components respectively and a minority of the first and second components respectively. A second sample of the second signal portion and a part of the first signal portion are combined to produce substantially the second component. In addition, a first sample of the first signal portion and a part of the second signal portion are combined to produce substantially the first component.

Abstract: Antenna system for double polarization in two high frequency bands of different frequency positions includes a orthomode transducer, in the following text called polarization filter having an antenna end terminal and two directional terminals, one being for right circular polarized waves, and the other being for left circular polarized waves. These directional terminals connect, respectively, with two frequency filters which separate the signals into the lower of the two high frequency bands, and the higher of the two high frequency bands. There are two 3-dB 90.degree. directional couplers, one of which handles right and left circular polarized signals of the lower frequency band, and the other of which handles right and left circular polarized signals of the higher frequency band. The polarization filter is constructed to be phase-symmetrical with respect to its transit paths.

Abstract: A constant resistance network which exhibits frequency dependent characteristics consists of a cavity resonator having two coupling loops mounted parallel to the walls of the cavity. The resonant frequency of the cavity is primarily determined by the dimensions of a resonator plate whose frequency of resonance can be trimmed by adjusting the size of a slot. The network can be used for combining the different frequencies by arranging that one of the frequencies is at the resonant frequency of the plate. The network can be extended by the provision of additional resonator plates to provide a more complex frequency response.

Abstract: Two main rectangular wave guides e.g. for telecommunications in GHz frequency bands are coupled by arms inclined for example at 60.degree.. This simultaneously simplifies machining of the coupler in the form of two symmetrical shells and also improves the electrical characteristics of the coupler.

Abstract: A planar millimeter wave microstrip triplexer for separating three contigs bands of frequencies (lower, middle and upper bands). The middle band is separated by the use of a diplexer comprising two quadrature couplers connected by dual identical planar bandpass filter sections. A second diplexer comprised of two edge-coupled filter sections is connected to the isolated port of the input quadrature coupler of the first diplexer. Signal components contained in the upper and lower frequency bands appear at the respective outputs of the second diplexer.

Abstract: A filter network for separating a transmitted communication frequency into discrete channels. A separator, exemplified by a triplexer, includes a pluggable mid-range high Q bandpass filter and a diplexer of low Q bandpass filters. Circulators receive signals reflected from the high Q filter and pass them to the low Q filters. A combiner circuit takes the attenuated signal from the low Q filters and sends it through a circulator to a high Q plug in filter where the signal passes through a circulator where it is combined with the signal from the high Q filter of the separator as output.