Development of Packaged G-Band Power Amplifier Based on INP HEMT Technology Utilizing Novel De-Embedding Techniques

Terahertz monolithic integrated circuits (TMICs) have broad application prospects in fields of high-resolution imaging radar and long-distance high data rate wireless communication for their tremendous advantages in terms of compactness and performance1. However, a key obstacle for the low insertion loss of terahertz integrated circuits is the development of practical packaging technology that allows TMICs to interface with rectangular waveguides. Due to increasingly higher reactance and losses with increasing frequencies, direct wire bond interconnects become impractical. As proposed by the author, an effective method is to de-embed the parasitic parameters introduced by gold wire bonding by optimizing microstrip line to waveguide (ML-WG) structure. Accordingly, a G-band monolithic integrated power amplifier based on InP HEMT technology was designed and packaged for demonstration. The 3-stage amplifier adopted a balanced topology design and all matching network of the amplifier was done through grounded coplanar planar waveguide (GCPW) transmission lines for reduction of transmission losses and suppression of parasitic substrate modes. It showed that the amplifier could achieve a 3-dB compression saturation output power of 40mW at 215 GHz and behaved good input and output return loss of greater than 20dB. Then, the MMIC was packaged within a cavity where the RF signal was transmitted from waveguides to microstrip circuits based on quartz substrate, then to GSG pads of MMIC through gold ribbon bonding. The ML-WG transition structure could be cleverly used to embed the parasitic effects of gold ribbon bonding through optimization in full-wave electromagnetic simulation software HFSS.