A single layer slotted waveguide array for 22 GHz band radio system between mobile base stations

Mobile communication has become popular and the number of base stations is growing rapidly. Planar antennas are required for a 22 GHz band wireless network which connects between a mobile base station and the central one. Three sizes of the antennas are considered for this use. The gain of the first one is (1) 33 dBi, the second one is (2) 39 dBi and the last one is (3) 45 dBi, for the 22.0-22.6 GHz and 22.6-23.2 GHz bands. A waveguide has a small transmission loss for its closed structure even at high frequency. Only a waveguide antenna can realize the subscriber radio system in such a high frequency and high gain range. However, the structure of the conventional slotted waveguide array is complicated and it has not been suitable for mass production in general. We proposed an "in-phase feed circuit" which consists of single layer /spl pi/-junctions in series and realized a simple structure and an easy manufacturing of the antennas. This paper presents a design of the antenna using resonant shunt slots; the slot design especially takes the mutual coupling into account. The antenna characteristics are confirmed by experiment in the 22 GHz band.<>