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This study proposed a high gain dipole antenna system with reflective metal sheet. The structure of this system was simple. An antenna unit was composed of a symmetric trapezoid-shaped dipole antenna, and an antenna system was constructed by placing metal reflective metal sheet, which were formed on single-sided base plate (FR4), of the same structure with a certain spacing. The area of the antenna system was 43 × 10 mm2. A 50 Ω copper coaxial cable was connected to the center of the antenna unit as the antenna feed. This system was designed specifically for WLAN applications. Having a frequency band of 2.4–2.485 GHz, the proposed antenna system had good directivity, and the gain was approximately 6.0–6.2 dBi.

A broadband probe-fed patch antenna with a novel three-dimensional (3D) U-shaped ground plane is proposed and experimentally studied. The proposed antenna has a thick air substrate, and by placing the two flanges of the U-shaped ground plane in parallel to and at a suitable distance from the radiating edges of the antenna's radiating patch, a wide impedance bandwidth (>25%) with much reduced cross-polarization radiation can be obtained, compared to the case with a conventional planar ground plane. In addition, enhanced antenna gain for the proposed antenna is also observed. Details of the proposed antenna and experimental results are presented and discussed.

This paper presents an omnidirectional high-gain dual-mode dipole antenna design with simple architecture. The proposed antenna system was composed of a rectangular antenna main body and a reflective ground plane. The antennas was "H" shaped and fabricated on a single-sided FR4 substrate. The area of the antenna system was 53 × 31 mm2, and a 50Ω micro-strip was used as a feeding pin at the center of the rectangular antenna main body. This antenna design included two frequency band ranges. For the Global Positioning System (GPS), the 1.57542 GHz frequency band was used. For WLAN, the 2.4–2.485 GHz frequency band was used. In the GPS frequency band the proposed antenna exhibited good omnidirectional properties and gain of 1.6–1.7 dBi. In the WLAN frequency band the proposed antenna exhibited good directional properties and gain of 6.2–6.3 dBi. This antenna design showed excellent performance when used for GPS and WLAN.

This paper presents a design using dual capacitive feeds to excite a patch antenna with a thick air substrate to achieve a wide operating bandwidth with reduced cross-polarization radiation. The dual capacitive feeds are fed by equal input powers, but with a 180° phase shift, and have a narrow conducting strip placed below the radiating patch, supported by a conducting post, which is then connected, through via holes in the ground plane, to the microstrip feed network. Experimental results show that the proposed antenna can have greatly reduced cross-polarization radiation across the entire operating bandwidth, compared to the case with a single capacitive feed. Details of the proposed antenna and experimental results are presented. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 169–171, 2000.

A new and simple technique for obtaining circular polarization (CP) radiation of a single-feed microstrip antenna is demonstrated. This CP design is achieved by insetting a single slit to the boundary of the microstrip patch, and placing a single feed along an axis 45° to the one containing the slit. Applications of this CP design method to square and circular microstrip antennas have been implemented. Typical experimental results are presented and discussed. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 306–308, 1998.

Broadband patch antennas with a thick air or foam substrate have been of considerable interest owing to their simple structure, easy fabrication, and good radiation characteristics over a wide operating bandwidth. However, when such broadband patch antennas are to be excited using a probe feed, achievable bandwidth is usually limited to be less than 10%, due to the large inductance associated with the longer probe in the thick substrate layer. To overcome this problem, there are usually some compensations or modifications to be introduced in the feed arrangement or some slot loadings to be added to the radiating patch. In this article we demonstrate a new and simple broadband design of a patch antenna with a pair of wide slits. The wide slits are inserted at the boundary of a circular patch or at one of the radiating edges of a rectangular patch. The proposed broadband patch antenna can have similar wide impedance bandwidth and good radiation characteristics as those reported for a U-slotted patch antenna. Details of the antenna design and experimental results are presented and discussed.

A broadband shorted-patch antenna fed by an aperture-coupled feed with an H-shaped coupling slot is proposed and experimentally studied. By using an air substrate with a thickness of about 0.07 of the free-space wavelength of the center operating frequency, the proposed antenna can have an impedance bandwidth of about 26.2%, which is comparable to the conventional broadband probe-fed patch antenna with a U-slotted or E-shaped patch. Good broadside radiation patterns for the proposed antenna are also observed. Details of the proposed antenna and experimental results are presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 306–307, 2001.

A new design of a circular patch antenna with an impedance bandwidth greater than 25% and a peak antenna gain about 8.3 dBi is presented. The circular patch antenna has a thick air substrate, and a pair of wide slits are cut in the circular patch to facilitate the antenna's impedance matching. The circular patch is supported by a conducting post, which is also connected to a 50 Ω microstrip feed line. The ground plane of the microstrip line also serves as the ground plane of the circular patch antenna, and the substrate of the microstrip feed line and the circular patch are on the same side of the ground plane. Details of the antenna design and experimental results are described. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 327–328, 2000.

A wideband circular-E patch antenna with an air substrate and a capacitive feed is proposed. The circular-E patch is formed by inserting a pair of wide slits at the boundary of a circular patch, and the capacitive feed has a small metallic disk placed below the circular-E patch, supported by a conducting post, which is then connected to a 50 Ω SMA connector through a via hole in the ground plane of the patch antenna. A prototype of the proposed antenna is constructed, and experimental results reveal that a group of three adjacent resonant modes can be excited, which results in a wide 10 dB return-loss impedance bandwidth of about 35%. Acceptable radiation characteristics for operating frequencies across the obtained wide impedance bandwidth are also observed, and the gain variation within the bandwidth is seen to be less than 1.4 dBi, with a peak antenna gain of about 7.9 dBi. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 134–135, 2000.

Novel design of a dual-frequency triangular microstrip antenna with a V-shaped slot is proposed and experimentally studied. By selecting suitable dimensions of the V-shaped slot, dual-frequency operation with the frequency ratio ranging from 1.488 to 1.834 has been obtained using a single probe feed, and the two operating frequencies are of parallel polarization planes. Typical experimental results of the proposed design are presented and discussed. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 20: 133–134, 1999.

A novel disk-sector microstrip antenna with specific flare angles for circular polarisation (CP) operation is proposed and experimentally studied. Results show that by selecting the flare angle of the disk-sector microstrip patch to be 65 or 70/spl deg/, right hand or left-hand CP radiation can easily be obtained using a single probe feed. Details of the design considerations are described, and measured CP characteristics are presented.

The broadband design of a triangular microstrip antenna with a U-shaped slot is demonstrated. With a foam substrate of thickness /spl sim/0.08 /spl lambda//sub 0/, a slotted triangular microstrip antenna with an operating bandwidth of /spl sim/18% is obtained, which is /spl sim/1.8 times that of a corresponding simple triangular patch antenna. Details of the antenna design and experimental results are presented.