전자기 결합을 이용한 위성방송 수신용 마이크로스트립 다이폴 어레이 안테나의 특성에 관한 연구

Abstract

This thesis describes a characteristics of microstrip EMC (Electro-Magnetic Coupled) cross dipole array antenna with circular polarization. EMC cross dipole array antennas are attractive elements with the desirable properties such as simplicity, small size, and circular polarization.

This thesis is composed of five chapters including the introduction. The chapter 2 explains a design for microstrip EMC cross dipole antenna element with a circular polarization and a wide bandwidth. The circular polarization is obtained by the X-shaped cross dipole radiation element. The wide bandwidth is realized by EMC technique. The antenna characteristics are analyzed by the Ensemble and the FDTD (Finite Difference Time Domain) method with Mur's 2nd order ABC (Absorbing Boundary Condition). The radiation power for uniform illumination in an array design is also controlled by offset parameters.

In the chapter 3, T-junction power splitter is presented. The characteristics of reflection and transmission coefficients were calculated.

The chapter 4 shows the performance of array antenna. The 20-element array antenna was designed and fabricated. The measured results agreed with the calculated ones. The beam-tilt characteristics are numerically obtained by control of element distance. The proposed beam-tilt antenna can be applied for DBS (Direct Broadcasting from Satellite) reception. When the distance between elements is 12 mm at 12 GHz, the radiation angle of array antennas is obtained -45°beam-tilt. Furthermore, the 40- and 80-Element beam-tilt array antennas were proposed for realizing high gain. By control of the element distance on the feed line in design, the array antennas with high gain and beam tilting angel of -45°could be realized. The axial ratio of 0.1 dB below was designed for the wide bandwidth. However, future work is to suppress the high grating lobe.

Then, it was concluded in the chapter 5.