Abstract: High efficiency transmit-receive switches in accordance with embodiments of the invention are disclosed. In one embodiment, a high efficiency transmit receive switch includes a power input coupled to a power supply, an amplifier output port and a transmit switch input port coupled to a circulator, a received signal circuit port coupled to a first PIN diode coupled to a second PIN diode via a first transmission line and spaced a fractional wavelength apart, the transmit switch input port is coupled to a third PIN diode coupled to a harmonic filter, a second transmission line coupled between the second PIN diode and to the third PIN diode, spaced a fractional wavelength apart, the transmit circuit signal port is coupled to an amplifier, the amplifier is coupled to the amplifier output port, the second transmission line is coupled to the bias current generator coupled to the output port.