Study on Low Back-lobe Short Leaky-Wave Antenna, Dual-Beam Scanning Microstrip Antenna, and Dual-Band High Isolation MIMO Antenna
Jou, Christina F.
|關鍵字:||低背瓣洩漏波天線;雙波瓣掃描微帶天線;高隔離度多天線系統;Low back lobe leaky wave antenna;Dual beam scanning microstrip antenna;High isolation MIMO system|
第四部分則是提出晶片型天線之應用。第一支提出的天線為實作在被動元件整合玻璃板材製程上，為一共平面波導饋入摺疊式偶極天線設計。而第二支所提出的天線則是實作在台積電 0.18微米製程上，差動式共平面波導饋入偶極天線設計。兩支天線都是特別針對特定頻帶應用而設計之晶片天線。第一支摺疊式偶極天線是應用在24GHz 頻帶，第二支偶極天線則是應用於PDH 微波通訊系統頻帶。 第一支天線為單一天線設計，輻射場形則是以天線鉛直面全向性輻射設計。而第二支天線則是與射頻混波器整合在單一晶片上，因此輻射場形則是以前端輻射場形設計，以降低天線輻射對射頻電路的干擾。|
This thesis consists of four parts: low back-lobe short leaky wave antenna, dual-beam scanning microstrip antenna, dual-band high isolation MIMO antenna and CPW on-chip antenna designs. In the first part, the low back-lobe short leaky wave antenna is proposed. Firstly, in order to reduce the reflected wave of the antenna, the tapering technology is utilized on the antenna design since the technology can disturb the current distribution. Next, the complementary split ring resonator (CSRR) structure is embedded on the open-end of the antenna. Because of the CSRR structure, the reflected wave caused by the open-end of the antenna can be suppressed. Hence, the back lobe radiation pattern of the antenna can also be suppressed effectively. There are two antenna configurations are proposed in this chapter. One of them is that the CSRR structure is on the antenna plane. For the other one, the CSRR is on the ground plane. Both of them can achieve the suppression of the back lobe radiation. In the second part, dual-beam scanning microstrip antenna is proposed. The antenna design is based on the conventional leaky wave antenna. The difference is that there two L-shaped slots are embedded on the ground plane of the antenna. Due to these two slots, another radiation beam beneath the antenna plane can be obtained. By this characteristic, the dual-beam radiation pattern is generated. The characteristic of the leaky wave antenna has been great significant affected since the L-shaped slots is embedded on the ground plane. One of the effects is that the propagation constant of the antenna is changed. Hence, the operating frequency band of the antenna shifts to lower frequency band. Another effect is the radiation beam beneath the antenna plane which is usually called side lobe is enhanced. However, the beam is enlarged greatly in this design to let the beam have the same characteristic with the beam above the antenna plane. Meanwhile, the two slots are the key parameters of this design such as the position, length, width and the spacing of the slots. The third part presents a dual-band high isolation MIMO antenna design. In this section, the decoupling theory is brief described that how to achieve the decoupling effect between two elements. In this design, the two elements are utilized by two dual-band monopole antenna. Next, the neutralizing transmission line structure is implemented in this design to reduce the coupling effect between the two monopole antennas. Therefore, the high isolation can be obtained for this MIMO antenna design. The fourth part proposes the applications of the on-chip antenna. The first design is the CPW on- chip folded dipole antenna which is fabricated by the Glass Substrate Integrated Passive Device (GIPD) process. This antenna is designed for 24GHz ISM band. The second design is the differential CPW on-chip dipole antenna which is implemented by the TSMC 0.18μm CMOS process. This antenna is designed for the PDH microwave communication system. The design of the radiation pattern of the first one is omni-directional on the vertical plane of the antenna. For the second design, the radiation pattern is designed as the end-fire configuration since this design is integrated with RF mixer circuit in one chip. This pattern is designed for reducing the interference which is caused by the antenna in circuit region.