The Analysis of Stub on Coplanar-Fed of Single and Array Microstrip Antenna for Mobile Satellite Communication

The microstrip antenna has small, lightweight shape characteristics, and limit performances. It is necessary to increase the performances, especially the axial ratio (Ar) of the previous antenna configured in two layers accompanying the capacitive coupling between them. If length of feeding line and width-to-length ratio of radiating patch are not matched, it can decrease the Ar performance. This paper discusses about the analysis of previous antenna (two layers) and modified antenna (one layer), optimized modified antenna using stub on coplanar-fed both single and array microstrip patch antenna for mobile satellite communication, especially for receiver antenna, Rx. The Method of Moment (MoM) is used to analyze the antenna with an infinite ground plane and substrate. The antenna is made of a thin patch conductor and a microstrip-line. The microstrip-line is located on the same layer which has the thickness h = 1.6 mm and uses a conventional substrate (relative permittivity, εr = 2.17 and loss tangent, δ = 0.0009). The patch conductor is fed by a coplanar-fed with microstrip-line to obtain a conformal configuration. The dual-fed type is to generate a left-handed circular polarization (LHCP) which is combined with an equilateral triangle patch. In this case, one of the microstrip-line feeds is set longer than the other to introduce a 900 phase delay. Moreover, the simulation results discuss about the three varies size of stub embedded on coplanar-fed and compare among of them to confirm that the antenna satisfy the target. The results of single antenna using stub-fed, especially for bandwidth of axial ratio below 3-dB and gain above 5 dBic are about 0.02 GHz and 0.065 GHz, respectively. The results of array antenna, in the case of bandwidth of axial ratio below 3-dB and gain above 5 dBic are about 0.03 GHz and 0.3 GHz, respectively. In addition, the result for axial ratio of the modified antenna and the previous antenna at 2.5025 GHz are 0.27 dB and 1.02 dB, respectively. It is caused a coplanar-fed which connected directly to the radiating patch (one layer antenna)

Circularly Polarized Stack-Patch Microstrip Array Antenna for ETS-VIII Applications

By using the H-IIA Launch Vehicle No. 11 from the Tanegashima Space Center, in the south of Kagoshima Prefecture Japan, ETS-VIII (Engineering Test Satellite VIII) has been launched successfully in the end of 2006. The ETS-VIII is one of the largest geostationary Sband satellites in the world to meet future requirements of voice and data communications, broadcasting and global positioning [1]. Backward-looking, there are various types of antennas which developed aiming at ETS-VIII [2]-[5]. A part of the antennas [3] have been experimented outdoor by use of a pseudo-satellite station. Moreover, in order to obtain a good performance antenna to clarify suitably result on frequency characteristic, return loss, and radiation pattern, and also to obtain a simple configuration such as small, light and low profile, a left-handed circularly polarized stack-patch microstrip array antenna is proposed. The antenna was calculated by the Method of Moments using probe-fed pentagonal array antenna as radiating patch and triangular array antenna as parasitic patch with dielectric relative permittivity 2.17 and loss tangent 0.0009. In this paper, it discuss about the performances of antenna above at El=48° both of calculation and measurement results, the examined of performance beam antenna at low elevation, and the performances of antennas to take in signal from ETS-VIII satellites. The measured results at El=48° agree well with the calculated results of 5 dBic gain, and the 3-dB axial ratio beamwidth of the whole azimuth range about more of 120° for each beam coverage in the conical-cut direction satisfy for ETS-VIII applications

Satellite Communications

This study is motivated by the need to give the reader a broad view of the developments, key concepts, and technologies related to information society evolution, with a focus on the wireless communications and geoinformation technologies and their role in the environment. Giving perspective, it aims at assisting people active in the industry, the public sector, and Earth science fields as well, by providing a base for their continued work and thinking