Millimetre Wave Signal Generation Using Monolithic HEMT Technologies

We have designed, processed and tested monolithic 40GHzfrequency doublers and amplifiers using enhancement and depletionHEMT processes. The passive parts included microstrip, coplanarwaveguide and lumped component circuits. The on-chip measuredoutput power of frequency doublers at 40GHz was +2dBm and the conversion loss was 2–;5 dB. The EHEMT doublersoperated at low input power level from a single DC supply andthe CPW passive parts enabled economical design. The integratedsystem of depletion PHEMT doubler and amplifier chips enclosedin hermetic packages delivered +10 dBm output powerat 38GHz frequency band. This is the first time that the applicationof enhancement mode HEMTs in frequency doublers is reported andcompared to the performance with depletion mode HEMTs. We haveproven that EHEMT and DHEMT frequency multiplier circuits areefficient solutions for local oscillator use in modern millimetrewave systems.