A Medium Power Solid State Amplifier for V-Band
A solid state amplifier for the 54 to 58 GHz band is described. The amplifier uses two layer InP Gunn devices. Three stages of amplification provide an output power of 100 mW at a gain of 15 dB. The small signal gain is 30 dB; the noise figure is in the 15.5 to 16.5 dB range. The design of a broadband low-loss V-band circulator, which was used in the amplifier, is also described.
Influence of Non-Ideal Circulator Effects on Negative-Resistance Amplifier Design
It is well known that the non-ideal properties of a circulator (non-unity VSWR, non-zero insertion loss, finite isolation) have a marked effect on the design of single-stage and multi-stage negative-resistance amplifiers. These effects are due to the frequency dependence of the circulator parameters, the feedback associated with multiple reflections between circulator ports and terminations, and the possibility of spurious pass-bands in the circulator characteristics away from the desired operating frequency range. Noise degradation also occurs with a low-noise amplifier circuit.
A simplified theory of the three-port junction ferrite circulator
A simplified theory of the three-port junction circulator is given. This theory is applicable to all three-port junctions which rely on the splitting of a pair of degenerate modes and gives the two circulation conditions of the three-port junction circulator in terms of the elements of the equivalent shunt resonator. This is done by first developing the degenerate normal-mode description of the resonator and then modifying it to allow for the known splitting of the resonant frequencies. The loaded-Q of the junction is also given. All the results obtained are consistent with the classical junction behaviour.