Design of a Partially-Corporate Feed Double-Layer Slotted Waveguide Array Antenna in 39 GHz Band and Fabrication by Diffusion Bonding of Laminated Thin Metal Plates

Miao ZHANG  Jiro HIROKAWA  Makoto ANDO  

IEICE TRANSACTIONS on Communications   Vol.E93-B   No.10   pp.2538-2544
Publication Date: 2010/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E93.B.2538
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Advanced Technologies in Antennas and Propagation in Conjunction with Main Topics of ISAP2009)
Category: Antennas
double-layer,  slotted waveguide array,  partially-corporate feed,  diffusion bonding,  thin metal plate,  

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Introducing diffusion bonding of laminated thin metal plates to the fabrication of slotted waveguide arrays enlightens the high potential and the feasibility of multi-layer antennas with high-performance. It is a promising process with low cost even for a double-layer antenna, because the number of etching patterns for thin metal plates is only five. In this paper, a double-layer antenna for broadband characteristics is designed in 39 GHz band as demonstration. A 20 20-element antenna is composed of 2 2 sub-arrays by installing a partially-corporate feed circuit in the bottom layer underneath radiating waveguides in the top layer. The five-element sub-arrays in both the feeding and radiating parts are designed first. A new structure for the last slot coupler with shortened termination is also proposed to avoid an extra slot-free region when assembling the neighbor sub-arrays. As the simulation results by HFSS, the maximum gain of 34.55 dBi with the antenna efficiency of 85.5% is estimated at 38.5 GHz. The test antenna is fabricated by the diffusion bonding of thin copper plates. As the measurement results, a very high aperture efficiency of 83.2% with the directivity of 34.5 dBi is realized at the center frequency of 38.75 GHz, where the antenna gain of 34.4 dBi with the high antenna efficiency of 81.4% is achieved. The bandwidth of 5.0% defined as 1 dB down from the maximum gain is achieved.