Beam-steerable integrated lens antenna with waveguide feeding system for 71–76/81–86 GHz point-to-point applications

The paper presents design of an electronically beam-steerable integrated lens antenna for 71-76/81-86 GHz point-to-point applications. The proposed antenna is based on a combination of a waveguide feeding system and a hemielliptical dielectric lens with the diameter of 120 mm. The waveguide feeding system has one WR-12 input port and four electronically switched WR-12 output ports. It is based on SP4T MMIC switch mounted on a PCB with tapered antipodal fin-line waveguide-to-microstrip transitions. The feeding system is connected to an array of four linearly arranged rectangular waveguide feed elements used to effectively illuminate the lens. Measurement results of the fabricated feeding system show that S11 level is below -8 dB in the whole 71-86 GHz frequency band. The average level of S21 in the 71-86 GHz band is about -7 dB with the deviations between four outputs less than ±1 dB and the isolation is greater than 20 dB. The measured gain value of the antenna itself exceeds 38 dBi at the center frequency of the considered frequency band. The half power beamwidth values for all beams are in the range of 1.7-1.9 degrees with the beams overlapping level around -3 dB that provides beam-scanning range over ± 3.4 degrees. High gain values and good beam-steering capabilities allow considering the designed lens antenna as a perspective one for millimeter-wave backhaul applications.