Practical Considerations of a Multi-Port Leaky-Wave Antenna Array for Direction Finding

An array of multi-port leaky-wave antennas (LWAs) for direction finding (DF) in the X-band is proposed based on a printed double-stub configuration and analyzed in terms of practical considerations of range and detector sensitivity. A <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3}\times \mathbf{1}$</tex> array of two-port LWAs operating at 8 GHz is designed to achieve a coverage sector of about 40° as an illustrative example. Using the beam-scanning property of periodic LWAs, the period of each antenna in the array is selected in such a way to be able to accurately estimate the angle of arrival (AoA) across this range. Full-wave simulations in Ansys HFSS are presented using a microstrip LWA on a FR4 substrate to demonstrate the direction finding capability. A received signal strength indicator (RSSI) approach is taken whereby the relative power measured at each port is compared with the radiation patterns of each antenna in the array to estimate the AoA. Practical considerations of the excitation source and power detector integrated circuits (ICs) are finally discussed.