Low cross-polarization antipodal tapered slot antenna with gain bandwidth enhancement for UWB application

The problems for the antipodal tapered slot antenna (ATSA) with impedance bandwidth greater than 10:1 including main beam tilt and split, high cross-polarization component, and low gain at high frequencies narrow its gain bandwidth. The concept of a dielectric sheet-covered ATSA (DATSA) exploiting the coupling between the antenna and dielectric sheets is adopted to solve the issue. The original ATSA and proposed DATSA are simulated, fabricated and tested. The simulated results show good agreement with the measured results. In the range of 3.68–50 GHz, S11 of both antennas are less than −10 dB. Measured far-field results present the DATSA could generate well-formed end-fire beam with low cross-polarization of less than −13 dB and achieve boresight gain of more than 10 dBi over the range of 10–22 GHz, more than 14.6 dBi over the range of 23–30 GHz, more than 16.5 dBi over the range of 31–40 GHz, and more than 14 dBi over 41–50 GHz. Compared to the ATSA, the average boresight gain increase of 5.45 dBi is achieved in the range of 10–50 GHz.