In this paper, a novel feeding technique is proposed to feed a printed rectangular ring patch antenna that attains high gain in two bands simultaneously. The prototype antenna exhibits good impedance bandwidths satisfying ISM 2.45/5.8 GHz achieving maximum gain of 9.56 and 10.17 dBi, respectively, with a stable radiation pattern.

This paper presents a simple antenna system for land vehicle communication aimed at Engineering Test Satellite-VIII (ETS-VIII) applications. The developed antenna system which designed for mounting in a vehicle is compact, light weight and offers simple satellite-tracking operation. This system uses a microstrip patch array antenna, which includes onboard-power divider and switching circuit for antenna feeding control, due to its low profile. A Global Positioning System (GPS) receiver is constructed to provide accurate information on the vehicle's position and bearing during traveling. The personal computer (PC) interfaces as the control unit and data acquisition, which were specifically designed for this application, allow the switching circuit control as well as the retrieving of the received power levels. In this research, the antenna system was firstly examined in an anechoic chamber for S parameter, axial ratio, and radiation characteristics. Satisfactory characteristics were obtained. As for beam-tracking of antenna, it was examined in the anechoic chamber with the gain above 5 dBic and the axial ratio below 3 dB. Moreover, good received power levels for tracking the ETS-VIII satellite in outdoor measurement, were confirmed.

In this paper, an indoor repeater antenna with high isolation for WCDMA application is proposed. The designed repeater has very small separation of 20 mm between the donor and server antennas. The antenna has two resonance frequencies to cover the WCDMA band from 1.92 GHz to 2.17 GHz. The fabricated antenna has VSWR below 1.5, gain over 8 dBi, and isolation between server and donor antennas less than -80 dB in the WCDMA band.

This paper discusses the design, fabrication, and measurement of four L-shaped-slot microstrip patch antenna for HiperLan2. The prototype consists of four L-shaped slots. To obtain suitable bandwidth, the form layer is inserted between the ground plane and substrate. The design considers various important factors that include the four L-slot's length, width, position, air-gap height, and feed-point position. Once these factors are optimized, a four L-shaped slot microstrip patch antenna is fabricated and measured. The measured results of the fabricated four L-shaped slot antenna are as follows: resonant frequency is 5.35 GHz, bandwidth is approximately 8.1% (VSWR < 2.0), and gain is 8-9 dBi. The experimental far-field patterns are stable across the pass band. The 3 dB bandwidth in Elevation and Azimuth are 69and 62, respectively.

In this study, a multiple U-shaped slot microstrip patch antenna for application to the 5 GHz band is designed and fabricated. To obtain sufficient bandwidth in the operating band, foam is inserted between the substrate and ground plane, the type of form is styrofoam, the coaxial probe source is used, and the position of the probe shift is adjusted from the center to the left. The measured result (5.02-5.955 GHz) of the fabricated antenna satisfies the conditions of VSWR < 2.0 in 5 GHz band (5.15-5.35 GHz, 5.47-5.725 GHz, 5.725-5.825 GHz), gain of 3.88-9.28 dBi, and broad radiation pattern.

In an attempt to enhance the impedance bandwidth and gain, a notched patch antenna is proposed that has a pair of L-strip feeders, and it has been experimentally studied. The enhanced features were confirmed and proved by comparing the proposed antenna with the antennae that have been reported in the relevant literatures. The experimental results showed that the impedance bandwidth (SWR2) of 35.74% and the peak gain of 8.69 dBi (at 2.17 GHz) were obtained by the frequency band under 2.5 GHz. Designed originally for PCS and IMT-2000 service band, the proposed antenna, with its simple structure, may easily be mass-produced and may have various commercial applications.