Design of a 4–12GHz frequency doubler MMIC based on InGaP/GaAs HBT process

A compact monolithic InGaP/GaAs HBT frequency doubler has been presented. This prototype MMIC is capable to provide efficient conversion gain and high harmonic rejection from 4 to 12 GHz at the output. In this frequency doubler circuit, a novel push-push circuit configuration is used. We optimized the measurement system by using a Network Analyzer, instead of the traditional Spectrum Analyzer. The whole frequency doubler chip operates from a single +5 V supply voltage and consumes only 110 mA of current typically. The circuit has conversion gain of 14 dB over the output frequency range and provides saturated output power of 14 dBm when the input power larger -18 dBm. The chip also achieves excellent fundamental and third harmonic frequency rejection better than 28 dBc. The total size of this compact chip is 1.5 mm². Thus, this frequency doubler can be used as a low-cost insertion block to achieve any stable local-oscillation signals by multiplying the high quality voltage controlled oscillators at low frequencies.