서강대학교

초록/요약

This thesis presents the design of power amplifier (PA) integrated circuits (ICs) operating in the submillimeter-wave region. This PA was packaged in a waveguide jig using waveguide to microstrip transition. A submillimeter-wave PA is presented using 250 nm InP HBT technology. In order to obtain high output power, a two-way power combiner using multimetal layers with differential outputs is proposed. This two-way balun has an embedded impedance-transformation function, which enables to design broadband and low-loss impedance matching networks of a PA. The balanced PA using cascode power cells and the baluns exhibits a measured small-signal gain of 9.0 dB or more with full H-band (220-325 GHz), and the measured output power of 9.7 dBm with a gain of 4.5 dB at 300 GHz. The chip size is as small as 0.49 mm  0.41 mm including DC and RF pads. The high operating frequency of these circuits make development of a functional packaging method difficult. In this thesis, waveguide InP HBT PA modules operating in the WR-03 band (220-325 GHz) using a waveguide-to-microstrip transition using dipole antenna with two directors are demonstrated. The fabricated transition with two directors on a 50 μm-thick quartz substrate exhibits a back-to-back insertion loss of 2.8 dB across H-band and return loss better than 10.0 dB from 221 GHz to 318 GHz. The WR-03 PA module exhibits a measured small-signal gain of 4.0 dB or more with full H-band (220-325 GHz), and the measured output power of 7.5 dBm with a gain of 4.3 dB at 320 GHz. Also, microstrip transitions using stub arrays and indented waveguides for wide circuits/wafers are also proposed.