Abstract: A subharmonic image rejection and image enhancement mixer for mixing millimeter wavelength signals using a low conversion loss technique is described. A local oscillator frequency from an external source is fed to a first subharmonic mixer and through a phase shifter to a second subharmonic mixer. The phase shifter delays the local oscillator signal by (90.degree./n), where n is the multiple of the subharmonic mixers and is greater than 1. The first and second subharmonic mixers mix the local oscillator frequency with an input signal, which includes a desired frequency and an image frequency, to produce an intermediate frequency having a desired component and an image component at a select phase. A 0.degree.-90.degree. hybrid separates and terminates the image component of the intermediate frequency.

Abstract: The invention provides frequency multiplier circuitry which may be used in the output section of high power microwave systems to efficiently provide higher output frequencies. Generally, one multiplier stage may be utilized to double the frequency of the input signal with several stages being cascaded to achieve even higher frequencies. The varactor diodes utilized in circuits of the invention are preferably constructed primarily of silicon carbide, which has many advantages when compared with current varactors constructed of GaAs or silicon. Some presently preferred embodiments utilize a four terminal varactor bridge instead of a single varactor diode. The invention also teaches several significant techniques for improving the bandwidth of the circuitry, thus allowing variation of the frequency of the input signal without significantly attenuating the output signal.

Abstract: Planar millimeter wave transceiver includes a plurality of patch antenna elements disposed on a substrate in right and left hand circular polarization. Microstrip feeds having an intermediate feed point, interconnect adjacent elements. First switches interconnect with the feed points of adjacent feeds and are alternately operable between first and second states for establishing azimuth and elevation. Second switches interconnected with the first switches are alternately operable between first and second states for establishing transmit and receive modes for the antenna and with phase compensation. The microstrip feeds, and the first and second switches are interconnected on the substrate without crossovers. Transmitter and receiver elements may also be incorporated onto the substrate to form an integrated transceiver.

Abstract: A microstrip L-band bipolar dielectric resonator stabilized oscillator (DRO) devised in a moderate size (2'.times.5".times.3.6"), low-cost, reproducible circuit. Embedment of back to back varactors in the DRO provide voltage tuning for phase lock application without compromise of noise performance. Extremely low phase noise with a low l/f noise corner is achieved and the DRO is essentially constant in frequency and output power over temperature, all due to unique circuit configuration. An internal buffer amplifier and dc regulatory circuits provide a DRO that is insensitive to frequency pulling due to load changes and power supply voltage leads. New standards of performance are accomplished that permit simplified stalo configuration with lower phase noise.

Abstract: A radar receiver protector having high isolation and low insertion losses due to a unique microwave assembly configuration is disclosed. The receiver protector includes at least one high power input protection stage and a sensitivity time controlled multi-level attenuation which together achieve rapid switching with a non-critical bias supply and circuit configuration and develop attenuation levels which are invariant with temperature and insensitive to diode parameters.

Abstract: The invention comprises a microwave oscillator using a stripline circuit. The active device utilized in the oscillator is a bipolar transistor. A microstrip circuit is coupled to the emitter of the transistor while the collector is coupled to ground. This generates a negative impedance characteristic at the base of the transistor at the operating frequency. The operating frequency is determined by a varactor which is series tuned with an inductor. The impedance of the series tuned circuit is transformed to match the input impedance of the transistor by a microstrip circuit. Microstrip isolation circuits are utilized to couple appropriate bias signals to the emitter and the base to establish the proper operating point for the bipolar transistor. The output signal is taken from the base circuit of the transistor through the series combination of two microstrip circuits and a capacitor. A second varactor is loosely coupled to the base circuit of the transistor to provide for fine tuning.

Abstract: A single varactor diode parametric amplifier is described which has a broadband termination at the upper sideband frequency in the pump waveguide. This termination presents an open circuit condition at the upper sideband frequency, which, in combination with an upper sideband fequency choke on the input signal circuit transmission line achieves low noise, high gain characteristics with minimum interaction with the input signal, pump, and idler circuitry. Theoretical noise figures can be obtained at low power consumption, high gain, and broadband performance.

Abstract: A parametric amplifier having a beam lead dual Schottky barrier diode fabricated on a single semiconductor chip across a waveguide cavity. Two anode leads are bonded to the adjacent waveguide walls for coupling to a pump source; and a common cathode lead is bonded to a signal circuit. Parasitic reactances are reduced by minimizing stray capacitance and beam lead series inductance.

Abstract: A parametric amplifier which includes series coupled diodes contained in a resonating wave guide for providing a low noise figure by limiting the impedance to the idler circuit and inhibiting current flow in the upper sideband circuit. The mechanism for inhibiting current flow of the upper sideband circuit is independent of the characteristic impedance of the resonating wave guide to provide a constant, low power requirement, with high gain and broadband performance.