Abstract: A harmonic reaction amplifier (HRA) apparatus and method using a directional filter, including an HRA input for receiving an input signal, a divider coupled to the HRA input, the divider for splitting the input signal into a first divider signal and a second divider signal, an amplifier coupled to the divider, the amplifier for amplifying the first divider signal and the second divider signal, a directional filter coupled to the amplifier, the directional filter to filter the first and second divider signals to produce a filtered first divider signal and a filtered second divider signal, a combiner for combining the filtered first divider signal and the filtered second divider signal to produce an output signal, the combiner coupled to the directional filter, and an HRA output coupled to the combiner, the HRA output to receive the output signal from the combiner. The HRA can be used in a microwave radio.

Abstract: The performance of microwave coplanar and other circuit boards is improved by providing local matching elements for adjusting the characteristic impedance of local transmission line segments to better match the input or output impedance of the particular devices to which they couple. This is accomplished by providing a conductive bridge over the active lead of the transmission line, thereby lowering its characteristic impedance. This is very useful for narrow transmission line segments needed to make contact to small active device and/or MMIC's and which otherwise exhibit a substantial impedance mismatch with such small elements.

Abstract: A broad-band lumped element ring hybrid is comprised of a .pi. equivalent of a transmission line which is coupled to an electric ground through either a plurality of capacitors or plurality of inductors. The plurality of capacitors which are coupled to ground are coupled together with an inductor, while the plurality of inductors which are coupled to ground are coupled together with a capacitor. A plurality of tank circuits are coupled to the .pi. equivalent to broaden the bandwidth of the ring hybrid. Each tank circuit comprises an inductor and a capacitor.

Abstract: A microstrip directional coupler which employs closed form solutions for compensating capacitance or inductance and odd mode characteristic impedance necessary to realize high directivity or match in microstrip directional couplers valid for tight and loosely-coupled sections. A microwave monolithic integrated circuit (MMIC) directional coupler with single capacitive or inductive compensation derives from a mathematical analysis using symmetry and reflection and transmission coefficients' equivalency. Closed form solutions for the compensating capacitance or inductance and a new odd mode characteristic impedance are generated. The results are implemented in single antisymmetric inductive and antisymmetric and symmetric capactive compensated versions.

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 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: An apparatus and method is disclosed for a balanced mixer having a fifth port capable of removing the intermediate frequency and the upper sideband frequency while acting as an open circuit to the RF and local oscillator input signals. The upper sideband signal is then dissipated in a distributed load designed so as not to reflect the upper sideband signal back into the transmission ring. Thus, a balanced mixer is disclosed that provides IF signals and removes other unwanted signals without corrupting later signals.

Abstract: An apparatus and method is disclosed for providing a planar disc resonator oscillator/amplifier which consists of a planar radial disc resonator, a substrate having a hole extending therethrough, a negative impedance device, and a conductor having a predetermined width. The oscillator/amplifier having an external quality factor dependent upon the width of the conductor and upon the distance between the centers of the planar radial disc resonator and the negative impedance device.

Abstract: An IMPATT diode oscillator wherein the diode is coupled to a first transmission line in turn coupled to a bias port at one end and to a coupled line transformer formed with a second transmission line at the other. A stabilizing load is coupled to the first transmission line between the diode and the bias port. A first tunable resonator controlling the fundamental frequency of the oscillator and a second tunable resonator controlling the second harmonic frequency of the oscillator are coupled to the first transmission line between the diode and the stabilizing load so that independent control of the fundamental and the second harmonic is attained in a temperature stable device.

Abstract: A transmission line microwave oscillator having two degrees of freedom wherein the real portion, R.sub.in, of the input impedence seen by the active device is adjustable by changing the coupling coefficient between and active device and a resonator and where the external quality, Q.sub.EXT, of the oscillator is adjustable by changing the coupling between the resonator and an output transmission line.

Abstract: A distributed inductive reactance is coupled to a terminating impedance at the interface of a combiner probe with a resonant cavity. The distributed reactance is implemented by a metal insert having a cavity interface and having a coupling portion, which is coaxial with a cylindrical dielectric and with a cylindrical cavity in an end of the terminating impedance.

Abstract: An optimized transmission line switch comprises a first high frequency diode and means for counteracting the capacitive component of the first diode. Unpackaged diode chips are utilized to avoid parasitics introduced by diode packages. A two diode switch installed in a reduced height waveguide section provides isolation comparable to prior art switches while providing greatly improved insertion loss.

Abstract: A modification of a Wilkinson combiner/splitter is described wherein, by means of selection of the characteristic impedance of the transmission media and the value of the combining impedance, the combiner/splitter may be matched to input and output impedance which are not the same.

Abstract: An efficient higher order mode resonant combiner in which a higher order mode accumulator cavity is adjusted to have the real part of its input characteristic impedance to be so minimized as to be less than the characteristic impedance Z.sub.o of the input circuit. When an active device is matched to this low, minimized value of cavity input impedance a mismatch results between the active device power source and the input to the combiner at undesired higher order modal frequencies. This resultant mismatch at undesired modal resonances obviates the need for mode suppression devices within the cavity which devices as taught in the prior art had detrimental effect of the efficiency of the combiner.

Abstract: An impedance transforming hybrid ring has a non-uniform impedance ring structure coupled to four ports. Two of the ports function as input ports, the remaining two as output ports. An arbitrary relationship exists between the impedance of the input ports and the impedance of the output ports. The power division between output ports may be selected as a matter of design choice. A broad band phase reversing network is utilized to provide an impedance transforming hybrid ring which efficiently operates over octave bandwidths. Design equations are provided and method for utilizing same are disclosed.

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 step change in the diameter of the inner conductor or the outer conductor of the transmission line with absorptive material having a shoulder abutting against the step change and tapering toward the opposite conductor with the radius of the absorptive material at the step change being sufficient to provide a characteristic impedance substantially equal to the characteristic impedance of the coaxial transmission line prior to the step change.

Abstract: In an oscillator or power combiner of the type operating at microwave, millimeter wave and above, apparatus for increasing the size, so that one or more active devices can be coupled to the oscillator, including a TM coaxial cavity operating at a predetermined frequency, which cavity has an output coupled thereto for removing power, and a second cavity operating at a dominant mode and coupled to the TM coaxial cavity, which second cavity assures efficient and spurious free operation of the oscillator or power combiner at the desired frequency.

Abstract: In a high power oscillator for frequencies on the order of microwave and above, a method and apparatus for tuning the oscillator in response to a control voltage applied thereto by utilizing a relatively low power varactor diode in a harmonic cavity coupled to the oscillator and without loss of efficiency.

Abstract: In an oscillator of the type producing microwaves, millimeter waves and above, apparatus and a method for increasing the size, so that one or more active devices can be coupled to the oscillator, including a first cavity operating at a higher order mode, which cavity has an output coupled thereto for removing power, and a second cavity operating at a dominant mode and coupled to the first cavity, which second cavity assures efficient and spurious-free operation of the oscillator at the desired frequency.