Design and Fabrication of a Coporate-feed Plate- laminated Waveguide Slot Array Antenna for 120GHz-band Dongjin Kim * , Jiro Hirokawa and Makoto Ando Dept. of Electrical and Electronic Engineering Tokyo Institute of Technology Tokyo, Japan {djdjkim,jiro,Mando}@antenna.ee.titech.ac.jp Tadao Nagatsuma Dept. of Systems Innovation Osaka University Osaka, Japan nagatuma@ee.es.osaka-u.ac.jp Abstract— We propose a double-layer slotted waveguide array antenna having a wide bandwidth and a high efficiency for 120 GHz band. The diffusion bonding of laminated thin metal plates provides high precision even in very high millimeter bands such as 120 GHz. We design a 16x16-element array antenna having 90% peak aperture efficiency with 33.4 dBi at 126.5 GHz. Keywords- plate-laminated waveguide; diffusion bonding; double-layer; slot antenna, corporate feed I. INTRODUCTION Recently, there is strong demand for millimeter-wave wireless links using 120GHz and higher bands for the increase in data rate needed to catch up with the expanding broadband society [1]. We are investigating the feasibility of the corporate-feed plate-laminated waveguide slot array antenna [2][3] for this demand. A 16x16-element antenna achieves 80% antenna efficiency with more than 32dBi over a 4.8GHz bandwidth in the 60GHz band. Etching patterns in the laminated plates can provide high precision and the diffusion bonding can give perfect electrical contacts among the plates even at such higher frequencies. In this paper, we design this antenna in the 120 GHz band to demonstrate the high performances. The proposed antenna shows high efficiency of 80 % over an 11.5 GHz bandwidth and the peak of the directivity is 33.4 dBi with 90 % aperture efficiency at 126.5 GHz. The 1-dB down gain bandwidth is 13.9 %. II. ANTENNA STRUCTURE AND DESIGN A. Structure The structure of the proposed antenna is illustrated in Figure 1. There are 16x16 radiating slots with 0.86 wavelength interval on the top layer fed by a corporate feeding network on the bottom layer. Figure 2 shows the layer information of this antenna. The upper layer of this antenna consists of three etching patterns. Three kinds of the etching patterns are for radiating slots (0.2 mm thickness), cavities (0.6 mm thickness) and coupling slots (0.2 mm thickness). The bottom layer consists of one etching pattern for the feeding network (0.6 mm thickness). All of the etching patterns are composed by laminating thin metal plates of 0.2 mm thickness. The total antenna size of the 16x16-element array is 41.5mm x 42.0 mm and the total thickness is 1.6 mm for the design frequency of 123GHz. Figure 1. Antenna Configuration Figure 2. Layer Information of the Antenna 3044 U.S. Government Work Not Protected by U.S. Copyright AP-S/URSI 2011