Miniaturization of 3-D Microstrip Antenna using fylfot-shaped Structure

In this paper, the circular polarization microstrip antenna(CPMA) with fylfot-shaped structure was designed and fabricated by combining the bended and cross-shaped structure, using the feature that if the length of microstrip patch antenna(MPA) is fixed to miniaturize the center frequency of 1.575GHz CPMA, currently being used in GPS system, width is shortened, and the feeding point moves to the center of the patch. Also, the method to miniaturize this antenna more and more was studied by introducing the 3-dimensional miniaturization method of the iris and folded structure. In the case of 3-dimensional fylfot-shaped structure, the size of the antenna was square with 25mm × 25mm for the design frequency, and 90° of phase difference by controlling the location of feeding point and width of patch. As a result, -15.8dB of reflection loss, 2.2%(36MHz) of -10dB bandwidth, 1.83dBd of gain, and circular polarization(CP) feature of axial ratio 1.55dB were obtained, and 90.1% of size reduction effect was achieved compared to the general CPMA size(76mm × 83mm).