77 GHz beam-switching high-gain end-fire antenna on LTCC

In this paper, a design of a 77 GHz beam-switching antenna on Ferro A6-M LTCC is presented. The antenna consists of three high-gain end-fire type antenna elements pointing at different directions. One element is active at a time and the appropriate element is selected using a commercial SP4T GaAs pin-diode switch. A design of a transition from a WR-10 waveguide to a microstrip line for radiation pattern testing purposes is also described. The transition covers almost the entire waveguide W-band and the measured reflection coefficient is below -10-dB between 77 GHz and 110 GHz. The total loss of the transition is only 1 dB at the maximum. Measured maximum gain of 9.2 dBi and a -3-dB beamwidth of about 40° are achieved for a single antenna element. Simulated radiation efficiency is 89%. Beam switching between three different directions is demonstrated with radiation pattern measurements at 78 GHz. Good agreement is achieved between the simulated and measured results. The presented antenna is a very promising candidate for high data rate short-range millimetre-wave applications.