An Amplifier-Doubler Chain With Conversion Gain Improvement Techniques

This paper presents an amplifier-douler chain to double the signal frequency from 21 GHz to 42 GHz with about 10 GHz bandwidth of output frequency. For the improvement of conversion gain, the doubler adopts the fully differential Gilbert structure which provides large bandwidth and high conversion gain. Meanwhile, an inductive series LC network is used to form resonant tank with the parasitic capacitance to suppress the second harmonic of input frequency, hence the conversion gain of doubler is improved. Once again, the RLC parallel resonant network is employed as load of doubler and power amplifier, and it can improve bandwidth and conversion gain, too. What's more, transformer matching networks (TMN) are adopted to optimize the bandwidth and conversion gain of amplifier-douler chain. Finally, the amplifier-douler chain which fabricated by IBM SiGe 0.13 mu m BiCMOS technology shows 6.1 dB conversion gain and -4.1 dBm saturation output power with 26.5 mA operating current and 2.8 V supply voltage, and the fundamental and 3rd harmonic rejection at 42 GHz are 17.5 dB and 38.6 dB, respectively.