Summary
International Symposium on Antennas and Propagation
2009
Session Number:2C4
Session:
Number:2C4-7
Design Optimization of Stacked Patch Antenna for Ultrawideband Application
Mohammad Tariqul Islam, Mohammed Nazmus Shakib, Norbahiah Misran, Baharudin Yatim,
pp.504-507
Publication Date:2009/10/21
Online ISSN:2188-5079
Summary:
Ultrawideband (UWB) communication systems have been recently received great attention in the wireless world. It is widely used technology in communications, radar, imaging and remote sensing applications [1]. It will be preferred that an antenna has bandwidth in excess of frequency range from 2.5 GHz to 10.25GHz to include the existing wireless communication systems such as WLAN system operating at 5.15 ? 5.825 GHz, IEEE 802.16 WiMAX system operating at 3.3 ? 3.6 GHz, C-band (3.7 ? 4.2 GHz) satellite communication systems and UWB band (3.1?10.6GHz) [2]. The antenna aspects of UWB systems differ significantly from those narrowband systems. The design of practical antennas that radiate efficiently over an ultrawide bandwidth continues to be a challenging problem [3]. Due to the attractive merits of low profile, lightweight, ease of fabrication and wide frequency bandwidth, patch antennas are currently under consideration for use in ultrawideband (UWB) systems. However, conventional patch antenna suffers typically from a few percent of bandwidth. For this reason much effort is made to develop techniques and find configurations to broaden its impedance bandwidth. Many studies have been devoted to investigating antennas for UWB radios. It is a common practice to use the stacked patches to increase gain and/ or impedance bandwidth of the microstrip antennas [4] .This reduces the impedance variation of the antenna with frequency, thus enhancing the impedance matching across a broad frequency band. Various arrangements of the stacked patch structures have been investigated [5]. In [6], several structures of stacked patches with a shorting wall were put forward to achieved a low profile of 0.024 λg with two layers of dielectric substrates (εr=2.33), but the maximum bandwidth falls back to 10%. A dual layer stacked patch antenna with 56.8% bandwidth has been proposed in [7] for UWB applications which does not increase the surface area and has a dimension of 26.5 X 18 X 11.5 mm3 . Another wide bandwidth by electromagnetically couple the V-shaped patch with the triangular PIFA has been proposed in [1]. UWB operation with 53% bandwidth has been achieved by folding the shorting wall of the triangular PIFA in their research. These techniques can also be applicable to dual-band and wideband applications, albeit more complicated geometrical configurations. More recently an ultrawideband suspended plate antenna consisting with two layers has achieved an impedance bandwidth of 72.7% [8]. A new antenna feed method [9] namely the folded-patch feed has been shown to improve the impedance bandwidth of a patch antenna. The rectangular U-shaped-slot patch antenna with a folded patch feed with the dimension of 18 X 15 X 7 mm3 is shown to have an impedance bandwidth of 53.5% (VSWR?2) [10] and an E-shaped patch antenna with a foldedpatch feed is described to have an impedance bandwidth of 73.78 % [9]. In this paper, a new antenna is proposed to adopt the folded plate slit feed with notched rectangular stacked patch which can dramatically improve the impedance bandwidth of a patch antenna. A wider impedance bandwidth is achieved compared to the design reported in [9].