This paper reports on X-band Gallium Nitride (GaN) chipsets for cost-effective 20W transmit-receive (T/R) modules. The chipset components include a GaN-on-Si monolithic microwave integrated circuit (MMIC) driver amplifier (DA), a GaN-on-SiC high power amplifier (HPA) with GaAs matching circuits, a high-gain GaN-on-Si HPA with a GaAs output matching circuit, and a GaN-on-Si MMIC switch (SW). By utilizing either combination of the DA or single high-gain HPA, the configurations of two T/R module types can be realized. The GaN-on-Si MMIC DA demonstrates an output power of 6.4-7.4W, an associate gain of 22.3-24.6dB and a power added efficiency (PAE) of 32-36% over 9.0-11.0GHz. A GaN-on-SiC HPA with GaAs matching circuits exhibited an output power of 20-28W, associate gain of 7.8-10.7dB, and a PAE of 40-56% over 9.0-11.0GHz. The high-gain GaN-on-Si HPA with a GaAs output matching circuit exhibits an output power of 15-30W, associate gain of 27-30dB, and PAE of 26-33% over 9.0-11.0GHz. The GaN-on-Si MMIC switch demonstrates insertion losses of 1.1-1.3dB and isolation of 10.1-14.7dB over 8.0-11.5GHz. By employing cost-effective circuit configurations, the costs of these chipsets are estimated to be about half that of conventional chipsets.

High-power T/R switch with GaN HEMT technology is successfully developed, and the design theory is formulated. The proposed switch employs an asymmetric series-shunt/shunt configuration. Because the power handling capability of the proposed switch is mainly dependent of the breakdown voltage of FETs, the proposed circuit can make full use of the characteristics of the GaN HEMT technology. The switch has a high degree of freedom for the FET gate widths, so the low insertion loss can be obtained while keeping high-power performances. To verify this methodology, T/R switch has been fabricated in X-band. The fabricated switch has demonstrated an insertion loss of 1.8 dB in Rx-mode, 1.2 dB in Tx-mode and power handling capability of 20 W in 53% bandwidth.