Compact Phase Corrected H-Plane Horn Antenna Using Slow-Wave Structures

In this letter, a compact phase correctedH-plane horn antenna is proposed. Slow-wave structures in the form of equally distributed square metal pins are symmetrically loaded inside the horn aperture along the center line of the broad walls. The loaded slow-wave structure has a great influence on wave around the center while having little influence on wave around the slant narrow walls. The phase difference between the center and the edges is reduced. Therefore, this technique can be used to improve gain of the traditional H-plane horn antenna or shorten its length with gain unchanged. A Ka-band prototype of the proposed antenna is designed, fabricated, and tested. A parent antenna without slow-wave structures is also fabricated for comparison. The measured results show that an average gain improvement of 0.8 dB from 26 to 33 GHz and 1.7 dB from 33 to 40 GHz is achieved.