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A printed slot antenna performs a bi-directional radiation with backward radiation of cross-polarization as the unwanted wave and a low gain due to no ground layer below the feedline. These characteristics can be altered by installing a ground conductor below the antenna to reflect the backward radiation. The height of the ground distance between the antenna and bottom part of the ground reflector usually a quarter wavelength to obtain an in-phase signal of the reflected wave which strengthens the antenna radiation to enhance the gain of the combined wave. The shape of the ground reflector determines the gain of the antenna. The square plain conductor has lowest gain performance, thus it is not put into consideration in this research. This paper investigates the performance of several ground reflector shapes to convert the bi-directional radiation and improve the gain of an equilateral triangular slot (ETS) printed slot antenna which has a gain of 4.5 dBic. A truncated cone reflector installed on the equilateral triangular slot antenna has better gain than square and cylindrical cup reflector. This better performance thanks to the functions of the truncated cone which not just as a reflector but also acts as a horn antenna. Due to the last function, the distance between tha antenna and the bottom part of the truncated cone is a half wavelength. Thus the size of the cone reflector is larger than the other two. The truncated cone reflector was fabricated using 3D printer technology and coated with a conductive material. Measured results of the truncated cone reflector present RHCP performance and a a peak gain of 11.9 dBic.

The first circularly polarized L-band synthetic aperture radar (CP-SAR) antenna on-board the small satellite mission GAIA-II is presented. The antenna is a deployable mesh reflector antenna, with gain larger than 30 dBic and narrowband around center frequency of 1.275 GHz. The main mission of GAIA–II is land deformation monitoring and disaster prevention and mitigation. The current work describes the development of a compact CP L-band antenna onboard the microsatellite CP-SAR, focusing the design & simulation of the reflector dish and structures.

Our laboratory develops L Band circularly polarized synthetic aperture radar (SAR) sensor for microsatellite (150kg class) using 3.6m diameter of gold coated parabolic mesh antenna. This presentation explains the specification, antenna deployment system, RF system, and characteristics of parabolic mesh antenna for the developed sensor. This sensor will be employed to monitor global land deformation in the future.

A satellite-tracking left-handed circularly polarised triangular-patch array antenna has been developed to support the next generation of mobile satellite communications using Japanese Engineering Test Satellite VIII. The targeted minimum gain of the antenna was set to 5 dBic at an elevation of 48° in the Tokyo area, for applications of about a hundred kbit/s data transfer. The antenna is composed of three equilateral triangular patches and fed by a dual-proximity feed. The influence of the array configuration on the characteristic of this antenna is investigated using a method of moments (MoM) approach and a simple point source model. The measurement of the fabricated antenna was then performed to confirm the simulation results. The result showed that the 10 mm distance between the patch apex to the centre of the array antenna satisfies the target. The frequency characteristic of the fabricated antenna is 0.7% shifted to the higher frequency, and the maximum gain is 0.9 dB lower than the simulation results. The result also shows that the characteristic of the patch array antenna satisfies the specification at elevation angle El=48°, especially the 5 dBic gain coverage of the results covers the whole azimuth angle in a conical-cut plane at El=48°.