Millimeter-Wave High-Power MMIC Switch with Multiple FET Resonators

Masatake HANGAI  Tamotsu NISHINO  Morishige HIEDA  Kunihiro ENDO  Moriyasu MIYAZAKI  

IEICE TRANSACTIONS on Electronics   Vol.E90-C   No.9   pp.1695-1701
Publication Date: 2007/09/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.9.1695
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Microwave and Millimeter-Wave Technology)
Category: Active Devices/Circuits
switch,  FET,  FET resonator,  millimeter-wave,  high-power,  low-loss,  MMICs,  

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A millimeter-wave low-loss, high-isolation and high-power terminated MMIC switch is developed, and the design theory is formulated. Our invented switch is designed based on a non-linear relationship between the parallel resistance of an FET and its gate width. Our measurements of the parallel resistance with different gate width have revealed that the resistance is inverse proportion to a square of the gate width. By using this relationship, we have found the fact that the multiple FET resonators with smaller gate width and high inductance elements realize high-Q performance for the same resonant frequency. Since the power handling capability is determined by the total gate width, our switch circuit could reduce its insertion loss, keeping the high-power performance. We additionally describe the design method of this switch circuit. The relationships between the gate widths of the FETs and the electrical performances are described analytically. The required gate widths of the FETs for handling high power signal are represented, and the design equations to obtain lower insertion loss and higher isolation performances keeping high power capability are presented. To verify this methodology, we fabricated a MMIC switch. The MMIC had insertion loss of 2.86 dB, isolation of 37 dB and power handling capability of more than 33 dBm at 32 GHz.