Two Types of High Gain Slot Array Antennas based on Ridge Gap Waveguide in the D-Band

Abstract

The recent introduced ridge gap waveguide shows huge strengths in array antennas in millimeter and sub- millimeter wave frequencies. Generally, gap waveguide supplies contactless characteristics in order to avoid the good electrical contact between the different metallic layers. Therefore, the gap waveguide structures are relatively simple to be fabricated in Ka-, V-, W-bands. As is well known, the conductor loss increases rapidly versus frequency in millimeter wave and submillimeter wave frequencies. Thereby, the increasing conductor loss above 100 GHz affects the antenna gain. In this work, we compare two types of antennas in the D- band. The full cooperate feed array antenna is wide band, avoiding the offset of main beam. However, the number of T - junction power dividers rapidly increases. Thereby, it is necessary to design a T- junction power divider with ultra-low reflection for a big array in the D- band so that the gain of the big array antenna enhances. On the other hand, a series feed antenna array is also a choice in the D- band. The series feed structure has advantages of less power dividers, easy design. Nevertheless, it is unable to avoid the long line effect, narrow bandwidth and main beam offset. The comparison between two structures has been done in the D - band in this work.