摘要 本論文主要是探討兩種寬頻天線。第一種為端射型的線性漸進式開槽天線（Linear Tapered Slot Antenna，LTSA），利用180度的相移器（Phase Shifter）作為此天線的饋入網路，成功的在Alron 25N的微波基板上實現且返回損耗在X-band(8 GHz-12 GHz)皆大於10dB以上，並且與模擬有良好的一致性。 第二種為螺旋型天線(Spiral Antenna)，傳統的螺旋型天線是由中央饋入（Central Feed），所以整體為三維結構，製作不易。本文採用由外部饋入（External Feed）中間導體上升的共平面波導（Elevated Coplanar Waveguide）繞成的天線，使得天線本體及饋入網路在同一平面上，能利用印刷電路技術的方式製作。此天線製作在FR4基板上，在2.5 GHz~8 GHz模擬與量測有很高的一致性。 Abstract In the thesis, two types of broadband antennas are studied. A linear tapered slot antenna is first designed. It is fed by a 180 degree phase shifter and fabricated on Arlon 25N of 0.457mm thickness and of 3.25. Measured return loss is better than 10dB at X-band(8 GHz-12 GHz) and shows good agreement with simulation. Spiral antenna is then investigated. Usually feeding the spiral antenna from the center is a 3-D structure and is hard to be implemented. Therefore, an external feeding is applied to an ECPW winding spiral antenna. The whole structure is completely planar and can be easily realized by printed circuit technology. This antenna is fabricated on FR4 substrate. The simulation and measurement results are in good agreement at 8 GHz~12 GHz.
