A Steerable 8 Element 73 GHz Transmitting Time Modulated Array

The Time Modulated Array (TMA) is a type of phased array rarely seen applied, though it has advantages over other approaches. A TMA produces a set of radiated beams that are harmonically related to a set of digital control signals. In this paper the first mmWave beam steerable prototype TMA operating at 73 GHz, using bespoke GaAs integrated circuits, is presented. The beam steerable system consists of RF hardware and an FPGA controller. Laboratory radiated tests show good agreement to theoretical expectations. A beam steering of 24 degrees is reported (i.e. +/- 24 degrees total achievable range) for the TMA first harmonic beam, and 44 degrees for the second harmonic beam. The peak measured radiated array gain is -5 dBi. The maximum capable radiated power is +21.9 dBm. An increased level of integration on-chip, based on the existing architecture, could provide an array gain of +3 dBi.