60 GHz Amplifier MMICs and Module for 60 GHz WPAN System

This paper introduces the design and the implementation of the 60 GHz amplifier MMICs and the module for the 60 GHz WPAN system with a RoF (radio-over-fiber) link. The MMICs were designed using ETRI´s 0.12 mum GaAs PHEMT 4-inch process. The MCLFs (microstrip coupled line filters) compared with the MIM (metal-insulator-metal) capacitors have greater stability and less effect by the variation of fabrication. The 60 GHz drive amplifier MMIC and the 60 GHz power amplifier MMIC were designed by 4-stage structures using the MCLFs instead of the MIM capacitors for unconditional stability of the amplifiers and yields enhancement. The fabricated 60 GHz drive amplifier (DA) MMIC achieves a small signal gain (S₂₁) of 22 dB, a gain flatness of 0.8 dB, an input reflection coefficient (S₁₁) of -12 ~ -9 dB and an output reflection coefficient (S₂₂) of -10 ~ -7 dB for 59.5 to 60.5 GHz. The fabricated 60 GHz power amplifier (PA) MMIC achieves an S₂₁ of 15 dB, a gain flatness of 0.04 dB, an S₁₁ of -12 dB, an S₂₂ of -12 ~ -11 dB and an output P_1dB of more than 14 dBm for 59.5 to 60.5 GHz. The chip sizes of the DA and the PA are 3.8 times 1.6 mm² and 3.7 times 1.6 mm ², respectively. The waveguide-typed module was implemented with a DA MMIC and a PA MMIC. And it performed an S₂₁ of 38 ~ 39 dB, a gain flatness of 1.2 dB, an S₁₁ of -29 ~ -26 dB, an S₂₂ of -16 ~ -14 dB and an output P_1dB of 12.3 ~ 14.3 dBm for 59.5 to 60.5 GHz. And the size of the module is 8.0 times 6.0 times 2.3 cm³