Siemens Aktiengesellschaft

Other

Mahesh Kumar

Raymond M Waugh

Tzu H Chen

Tzu-Hung Chen

There is described a 2.times.2 switch matrix which includes four 1.times.1 switch matrix modules. Each 1.times.1 switch matrix module consists of an active power divider switch (APDS), an active power combiner switch (APCS) and an air bridge crossover. Additional APDSs and APCSs are utilized in the matrix to compensate for path length differences between different input to output signal paths thus providing good phase and amplitude tracking. The basic switch matrix modules are utilized to form a 2.times.2 switch matrix whereby two primary input ports can be connected to any one of two primary output ports. The 2.times.2 switch matrix is utilized to formulate larger matrix arrays as N.times.M configuration. Each of the active power divider switches and power combiner switches utilize two separate dual gate FETs which are suitably interconnected, depending upon whether the circuit is to be used as a power combiner or power divider. The other gate electrodes of the dual gate FETs are used as control terminals to receive an adequate bias voltage to therefore determine the power distribution or power combination characteristics of each of the devices and hence to control the coupling between input and output terminals.

Digitally controlled monolithic switch matrix using selectable dual gate

A monolithic double balanced mixer with a high third order intercept point employs a local oscillator signal which is applied to the input port of a first active distributed element balun. The balun has two outputs which are applied via amplifiers to respective inputs of a double balanced resistive FET quad mixer. The double balanced resistive FET quad mixer employs four MESFETs arranged in a ring configuration. Two additional inputs to the quad mixer are obtained from a second balun which is also of an active distributed element configuration and receives at the input the RF signal. The quad mixer operates to produce mixing of the LO and RF signals at the outputs thereof. The outputs of the quad mixer are applied to a combiner which operates to combine the outputs of the quad mixer to produce at the combiner output an IF signal. The combiner can be a common gate combiner configuration with active loads or a distributed configuration employing FET devices in a distributed transmission line type of circuit.

Monolithic double balanced mixer with high third order intercept point

A digitally controlled active phase shifter with vernier control consists of a 180 degree phase bit in series with a 90 degree bit and a digitally controlled active vector generator with vernier control. The digitally controlled active vector generator consists of an active power divider with digitally adjustable amplitude, a pair of phase delay networks with an active power combiner employing vernier control. The power divider consists of two sets of parallel pairs of FET's in cascode configuration with all input nodes connected together and all output nodes from the same set tied together. The FET at the output node of each pair is a common gate configuration with its gate RF grounded through a bypass capacitor. The gate bias voltage is applied to the common gate FET to switch it ON or OFF to thereby provide a set of desired signal amplitudes which can be obtained by selecting the gain of each of the cascode stages in each of the parallel pairs. Two output signals from the power divider are fed into a pair of phase delay networks to get 90 degree phase differences. The two 90 degree out of phase signals are then combined by an active power combiner which consists of two pairs of FET's in cascode configuration with their output nodes connected together. The combined signal while maintaining constant amplitude can have phase variations beteen 0-90 degrees according to the amplitude ratio of the two 90 degree out of phase signals. The gate bias voltage applied to the two common gate FET's of the power combiner can be varied continuously to give additional phase variations of the combined signal at the output.

Digitally controlled monolithic active phase shifter apparatus having a

Amplifiers operating in push-pull are implemented to obviate input baluns and output signal combiners and their attendant losses. Amplifiers having two signal branches that each receive the input signal and have their signal branch outputs connected directly together. Each branch operates during alternate half cycles of the input signal while direct combining of the branch signal outputs produces a composite signal corresponding to the complete input signal. Each branch includes a matching input circuit and a heterojunction bipolar transistor whcih may be configured in either common collector or common emitter arrangement. The transistors are different since one is an NPN while the other is a PNP but they are selected to have similar direct current and radio frequency characteristics.

High efficiency amplifier

A broadband monolithic balanced mixer employs a unidirectional active 180.degree. hybrid. The hybrid is fabricated utilizing two active signal splitters, two all pass phase shifting networks and two active signal combiners. The all pass networks provide a controlled phase response while the absolute phase of the network varies with frequency whereby the frequency difference between the two networks remains constant at 180.degree. over a very broad frequency range. Because the phase varies with frequency, the source and load impedance are rendered equal and resistive. Thus the above-described apparatus employs a common source FET with feedback for the signal splitter and a common gate FET for the combiner. Matching networks are used at all four ports of the active hybrid to achieve the desired match over the desired frequency ranges. The outputs of the hybrid are applied to suitable mixer circuits including FET or diode devices.

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Lawrenceville, NJ, United States of America

Mahesh Kumar