A chip set of low phase noise MMIC VCOs at C, X and Ku band in InGaP-GaAs HBT technology for satellite telecommunications

This work presents the design of three low-phase-noise monolithic voltage controlled oscillators (VCO) with a 2-μm InGaP-GaAs HBT technology for wideband satellite communications at C, X and Ku frequency bands. A large-signal design approach for the minimization of low-frequency noise up-conversion in conjunction with the optimization of the varactor-tuned integrated resonator were adopted for the minimization of phase noise (PN) generation. The C-band circuit implements a fundamental-frequency topology, whereas the X-and Ku-band oscillators are designed with a push-push configuration for PN and bandwidth optimization at higher frequency. The VCOs feature integrated output buffers for higher output power and improved load pulling. In the push-push VCOs, an integrated differential amplifier is used to provide an f0/2 prescaler output. Measured VCO frequency range of 3.31-4.17 GHz, 7.38-8.88 GHz, 10-12.28 GHz have been achieved, with maximum phase noise levels at 1 MHz offset from the carrier of -129 dBc/Hz, -124 dBc/Hz and -122 dBc/Hz respectively.