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 1.575 GHz 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 25 mm times 25 mm for the design frequency, and 90deg of phase difference by controlling the location of feeding point and width of patch. As a result, -15.8 dB of reflection loss, 2.2%(36 MHz) of -10 dB bandwidth, 1.83 dB of gain, and circular polarization(CP) feature of axial ratio 1.55 dB were obtained, and 90.1% of size reduction effect was achieved compared to the general CPMA size(76 mm times 83 mm)