A MMW T/R front-end for TDD radio systems

A MMW (millimeter-wave) transceiver (T/R) frontend which used in the Time Division Duplex (TDD) radio systems is designed and implemented in this paper. The T/R front-end with a frequency range from 40.518 to 40.638GHz consists of a transmitter channel and a receiver channel, while they share a public pathway which contains a set of switches (as a TDD switch) to the single antenna. A local oscillator (LO) multiplier-amplifier chain which offers the necessary LO power is also included. The circuits are fabricated on 127μm thick Rogers Duroid 5880 substrate by hybrid integrated circuit technology. Experiments results present that the T/R switching time is just within 10ns and the isolation is over 70dB, the noise figure is remained below 5.4dB, as well as the output power and the receiver gain reach to over 21d Bm and 10dB, respectively. The structure of the front-end is compact, with the size of 60mm × 50mm × 15mm.