Wen-Chung Liu

Design of Triple-Frequency Microstrip-Fed Monopole Antenna Using Defected Ground Structure

A novel triple-frequency microstrip-fed planar monopole antenna for multiband operation is proposed and investigated. Defected ground structure (DGS) is used in this antenna, which has a rectangular patch with dual inverted L-shaped strips and is fed by a cross-shaped stripline, for achieving additional resonances and bandwidth enhancements. The designed antenna has a small overall size of 20 × 30 mm2, and operates over the frequency ranges, 2.14-2.52 GHz, 2.82-3.74 GHz, and 5.15-6.02 GHz suitable for WLAN 2.4/5.2/5.8 GHz and WiMAX 3.5/5.5 GHz applications. There is good agreement between the measured and simulated results. Experimental results show that the antenna gives monopole-like radiation patterns and good antenna gains over the operating bands. In addition, effects of both the length of the protrudent strips and the dimensions of the DGS for this design on the electromagnetic performance are examined and discussed in detail.

Implantable Broadband Circular Stacked Pifa Antenna for Biotelemetry Communication

A compact circular stacked planar inverted-F antenna implantable for biotelemetry communication in the 402–405 MHz medical-implant-communication-service (MICS) frequency band is presented. By properly embedding a circular hook-shaped slot to each radiating patch of the proposed PIFA structure, antenna size and impedance bandwidth can be significantly improved. The constructed antenna presents a broad 10 dB impedance bandwidth of 84 MHz from measurement by inserting it inside the skin-simulating fluid. Also, the proposed antenna has characteristics of a compact size with a radius of only 5 mm, a radiation efficiency of 1.3%, and a monopole-like radiation pattern suitable for implantable device use.

Miniaturized Asymmetrical CPW-fed Meandered Strip Antenna for Triple-band Operation

By inserting different shaped slots into a rectangular patch printed in a single layer, a miniaturized design of a triple-band meandered monopole antenna fed by a coplanar waveguide (CPW) feeding line with two asymmetrical ground planes is presented. The proposed antenna with overall size of only 9 × 17 mm2 explores good triple-band operation with −10 dB impedance bandwidths of 11%, 15.4%, and 18% at 2.45, 5.21, and 7.27 GHz, respectively, covering the 2.4/5.2 GHz WLAN operation bandwidths. Also, consistent radiation patterns and good antenna gains across the triple bands have been obtained.

Triple-Band Planar Monopole Antenna for DMB/WLAN Applications

A simple microstrip-line-fed monopole antenna for triple-band wireless applications is presented. By properly loading folded strips along the edges of a stair patch, the designed antenna with, including ground plane, only 30 × 30 × 1.6 mm3, can lead to good impedance matching in a triple-band covering DMB (or L-band DVB-H) and 2.4/5.2/5.8 GHz WLAN operations. Prototype of the proposed antenna has been constructed and experimentally studied. The measured results not only explore good triple-band operations with wide −10 dB impedance bandwidths of 110 MHz, 730 MHz and 1.35 GHz at the 1.45, 2.43 and 5.58 GHz bands, respectively, and good radiation performances, but also show agreement with the numerical predictions.