Comments on GaAs MESFET baseband-to-microwave passive switches

Abstract

In two recent publications on broadband passive GaAS MESFET switches (ibid., vol.36, no.12, p.1604-13, Dec. 1988 and IEEE Trans. Electron. Devices, vol.ED-34, p.2595-602, Dec. 1987), M.J. Schindler et al. presented the low-power, low-frequency characteristics of these useful components. While complete characteristics were presented over the microwave spectrum, power-handling capability was not presented below 3 GHz. The commenters emphasize that the power-handling capability, as well as related nonlinearities such as total harmonic distortion, degrades significantly at lower frequencies in previously reported GaAs MESFET switches, and they expect similar characteristics in these recently reported switches as well. While this power-handling reduction is not significant for most RF and microwave users, there are negative implications for broadband, baseband applications such as instrumentation and signal processing.