無線電波感測技術之電路與天線

Abstract

本論文提出多天線無人機定位雷達和超寬頻室內外定位系統及其應用於無線電波感測定位之電路與天線結構，來提升定位精準度及縮小化。多天線無人機定位雷達不需要發射器即可偵測到無人機的動向及位置，亦完成高指向性及波束切換功能之天線陣列架構以將基地站小型化，此架構以4X4的巴特勒矩陣整合縮小化準八木天線來實現，波束形成矩陣可以提供相位差來切換主波束到系統中所需的方向，縮小化準八木天線結構為半圓環耦合串接，相比於一般微帶天線、八木天線、號角天線等其尺寸較小，且有主波束前傾(forward)的效果。 另提出超寬頻室內外定位系統其在數十公尺定位範圍內精準度仍達成公分等級的的定位誤差，超寬頻室內外定位系統偵測系統範圍需要在數公尺到數十公尺內都要達到公分等級的精準度，而定位系統易受到天線特性及極化影響導致定位誤差變大，需要一全向性圓極化天線。所有角度的增益皆相同且為圓極化，而有接近全向性圓極化特性的天線很少，有此特性天線的頻寬也都很窄，此一寬頻近全向性圓極化天線，|S11|小於-10 dB且在 的軸比(Axial Ratio, AR)小於3 dB的頻寬為14 %，XY平面AR皆小於3，XZ、YZ平面約θ=30~150、-30~-150 度的AR皆小於3，故此提出天線成功改良超寬頻室內外定位系統的精準度，使系統偵測精度不會因系統天線擺放方向使天線極化不匹配導致定位誤差變大。

This thesis proposes two wireless radio sensing positioning circuits and antennas for the multi-antenna drone detection radar and the ultra-wideband indoor/outdoor positioning applications. For drone detection radar system without the transmitting device, the signal analyzer, the single-pole six-throw switch, the low-noise amplifier, the micro-controller, and the high directional beam-forming antenna array are utilized to construct the detection radar system. A novel and compact microstrip Yagi-Uda antenna with the 4X4 Butler matrix is designed and implemented to obtain the beam-forming antenna array system. By using the proposed array system, the phase shifter can be removed in the beam-forming antenna array system and the dimension of the proposed microstrip Yagi-Uda antenna is reduced from 0.367λ0 to 0.188λ0 compared to the conventional series microstrip patch antenna. It is beneficial for constructing the compact multi-antenna drone detection system. For the ultra-wideband indoor/outdoor positioning system, a novel circular polarization antenna with the quasi-isotropic radiation characteristic is designed and implemented to achieve the high positioning accuracy. The proposed antenna exhibits the 500 MHz impedance bandwidth and 770 MHz axial-ratio bandwidth. At the 3.5 GHz operating frequency, the 3-dB axial ratio on the XY-plane of the proposed antenna for all angle of φ is achieved. Moreover, the 3-dB axial ratio on the XZ plane at θ=30~150 and-30~-150 degree, and the 3-dB axial ratio on YZ plane at θ=30~150 and-30~-150 degree is also obtained. The proposed antenna is connected to the DecaWave communication module consisting of DWM1000 transceiver to experimentally validate the usefulness of proposed system’s positioning accuracy.