A 15 GHz single stage GaAs dual-gate FET monolithic analog frequency divider with reduced input threshold power

An analog frequency divider is considered that operates on the basis of induced subharmonic oscillation and is composed of a mixer, a bandpass filter, amplifiers, and a feedback circuit. Although this frequency divider is inherently suitable for high-frequency operation, it possesses two substantial drawbacks: a complex circuit configuration is needed because of poor separation of the signals, and the input threshold power is undesirably high. The authors intend to mitigate these drawbacks by using a dual-gate FET mixer to improve the isolation of the signals, and by introducing a rejection filter at the output port to increase the conversion gain. The dual-gate FET contributes to simplifying the circuit configuration and the rejection filter results in reducing the input threshold power. The design, fabrication, and testing of the resulting 15-GHz single-stage monolithic GaAs FET analog frequency divider are described. Measured input/output characteristics at 14.8 GHz are given, and a high conversion gain of 0.0-2.5 dB is obtained for an input power of 2.0-9.5 dBm.<>