Performance Characterization for Patch Antenna Systems with a Limited Number of EBG Cells using the Mushroom-Like Structure as Benchmark

TitlePerformance Characterization for Patch Antenna Systems with a Limited Number of EBG Cells using the Mushroom-Like Structure as Benchmark
Publication TypeConference Paper
Year of Publication2007
AuthorsRuvio, G, Ammann, MJ
Conference NameIEEE AP-S International Symposium on Antennas and Propagation
Conference Start Date10/06/2007
PublisherInstitute of Electronic & Electrical Engineers
Conference LocationHonolulu, Hawai'i, USA

Electromagnetic Band Gap (EBG) structures have been demonstrated to be a powerful tool to improve the performance of microstrip antennas in terms of gain, side lobes reduction and coupling between adjacent elements of an array. The most successful configuration implies the radiating printed element properly surrounded by arrays of EBG cells. However, the introduction of EBG cells all around the microstrip antenna generally involves a size increment of the ground plane of the antenna system. This behavior becomes particularly critic especially for low frequencies applications (i.e. GPS, Galileo, Mobile telephony), where the insertion of EBG cells around the radiator generates a too large structure for practical utilizations. Even though the best performance is usually obtained with more that one single row of EBG cells around the radiator, sometimes for size economy, a compromise between compactness and improvement must be considered. On the other hand, when a limited number of EBG cells are inserted into the antenna system, some bandgap investigation techniques might be inappropriate. For instance, techniques based on dispersion diagrams of an infinite array of EBG cells might be too optimistic to describe a system with just one line of EBG cells. In this paper we use the very well-known mushroom-like EBG structure introduced as benchmark to evaluate the benefit of one, two or three rows of EBG cells. Moreover, it will be demonstrated that one single row of EBG cells is able to act as an attenuator of surface waves. This means that a certain improvement of the printed antenna under test is already visible when just a single row of EBG cells is inserted into the antenna system. Sometimes such enhancement is enough to meet wanted requirements with a feasible size enlargement of the overall antenna system. All the investigation carried out in this paper is obtained by using the Finite Integration Time Domain technique.

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