International Symposium on Antennas and Propagation
A Compact Leaky-Mode Antenna Array
Guang-Fu Cheng, Ching-Kuang C. Tzuang,
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This paper descirbes a novel 21-element, central-series-fed, proximity-coupled, leaky-mode antenna array. Due to the advantages of wide operation bandwidth, frequency scanning, less strangent requirement of tolerance, leaky-mode antennas had been widely developed and operated ay the first higher order mode on microstrip line-. Various methods of exciting the first higher order leaky mode of a microstrip line have been developed. The microstrip leaky-mode antenna showed a narrow radiation beamwidth in H plane, but wide beamwidth in E plane. Therefore a linear antenna array was developed for producing a narrow pencil beam -. Traditional leaky-mode antenna array designs, however, occupied relatively large area and complicated at the feeding structure . The leaky-mode antenna array reported in this paper is designed, keeping the feeding network at the minimal real estate that can be possibly achieved. Simple feeding network, however, can reduce the antenna size, path loss in transmission medium. The novel feeding method is broadband and is suitable for versatile applications for meeting various requirements. The microstrip antenna array presented in this paper is also operated at its first higher order mode. The leaky-mode radiation is achieved by coupling of the feed line and the leaky line with a small gap. Furthermore the antenna array is fed at the central symmetry plane. Therefore the amplitude distribution of the radiation pattern can be made more symmetric with lower side lobe level. The feeding structure provides a simple interface with microwave circuit without any transition. Thus no complicated feeding network and transition circuit are required, rendering compact and efficient integration with circuits such as low noise amplifier and power amplifier.