Differential grid array antenna to radiate pencil beam at 24 GHz for radar and sensor applications

A new differential grid array antenna that radiates a pencil beam is reported. The difference between the half-power beam widths of the E- and H-planes is used to assess the pencil beam quality. Also, a novel differential feeding scheme that eases the testing and improves the pencil beam quality, impedance matching and gain bandwidth is proposed. The prototype was designed and fabricated on RT/duroid 5880 substrate with the size of 40 × 50 × 0.787 mm³ and the number of 16 radiating elements. Measured results show that the differential grid array antenna achieved 4.37% impedance bandwidth and 17 dBi gain at 24.25 GHz.