International Symposium on Antennas and Propagation
An E-Band Partially-Corporate Feed Slot Array with Laminated Quasi Double-Layer Waveguide Structure and PMC Terminations
Miao Zhang, Jiro Hirokawa, Makoto Ando,
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Authors have developed various types of single-layer slotted waveguide arrays with simple structure and high mass-productivity. Those arrays have been successfully applied to relatively narrowband commercial services for satellite broadcast reception in 12 GHz band and wireless IP access at home in 26 GHz band etc. However, one weak point of that antenna is that the bandwidth of the antenna gain is restricted due to the long line effect resulting from the series-fed structure. For larger bandwidth, partially-corporate and corporate waveguide feeding circuit in the same layer with the radiating elements  have been developed by keeping the simple antenna construction at the expenses of enlarging the element spacing and the degradation in sidelobe. A double-layer antenna with a feeding circuit installed underneath the radiating waveguides deserves more expectations. A suitable fabrication technique for the realization of double-layer antenna in millimeter-wave band is also an essential issue. In this paper, a double-layer partially-corporate feeding structure [2, 3] to feed only two elements in series is introduced to enhance the bandwidth by reducing the long line effect in a series-fed array antenna. A 16×16-element array, which can be decomposed into 16 4×4-element sub-arrays, is to be realized demonstratively in the E-band. The fabrication technique called "diffusion bonding of laminated thin metal plates" [3, 4] is to be applied in the realization of double-layer antennas. The diffusion bonding is a process to realize stable surface bonding by applying plastic deformation and atom diffusion motion under the condition of high pressure and high temperature (~1000°C) in a protective atmosphere or vacuum. Etching of thin plates has the features of high precision around 20μm and low cost. The number of etching patterns is only five for the double-layer waveguide slot array . Relatively long processing time of the diffusion bonding is not serious if a large number of antennas are processed simultaneously.