Design of a 24 GHz reconfigurable transmitarray element with continuous phase range

This paper presents a reconfigurable transmitarray antenna unit cell for a frequency of 24 GHz. A continuous phase range is obtained by loading patches with varactor diodes on the outer layers of a printed circuit board (PCB) while the signal couples through slots in the inner layers. The design, numerical and experimental characterization of the unit cell in a rectangular WR-42 waveguide are reported. A phase tuning range of 120° was achieved with a custom layer stack which could be extended to 145° using solely RF-substrates.