用於雷達收發器間耦合路徑辨識之多因子寬頻分析法

Abstract

在現今高頻高速電路之發展下，電路講求在更小之尺寸以達到理想或更高之效能；而高頻之應用也使得電路愈做愈小。有鑑於雷達感測器之尺寸受限於天線布局而無法大幅地縮小，因而研究將雷達感測器 IC 晶片與天線設計於不同側的。儘管有助於大幅縮小尺寸，但結構中也產生了嚴重之雜訊干擾問題，致使雷達板接收端收到非預期之雜訊。本論文提出雜訊耦合關鍵路徑之分析方法，針對可能導致雷達測試板受到非預期干擾之雜訊耦合路徑，進行模擬與分析；並且，提出多因子寬頻分析法，以找到影響收發天線訊號隔離度之關鍵路徑及排序。此外，針對此類IC晶片與天線佈局於不同側結構之關鍵雜訊耦合路徑，而提出改善之結構，用饋入線換層結構抑制關鍵路徑之雜訊耦合，可以降低雜訊 18 dB，使收發天線間之干擾降到約 -70 dB，以達到雷達收發雜訊之需求，藉以協助雷達測試板之優化開發。

With the development of high-frequency and high-speed circuits, achieving optical or enhanced performance within compact dimensions has become crucial. The overall size of radar boards decreases as the operating frequency increases. However, the reduction in the radar board size is constrained by antenna layouts. This research focuses on a structure where the sensor IC and antennas are placed on opposite sides, enabling a significant size reduction. While this design offers substantial benefits in compactness, it also introduces severe electromagnetic interference issues. In radar transceiver systems, multiple coupling paths between the receiver and transmitter can lead unexpected coupling noise. To address this, this research proposes a multi-factor broadband analysis method to extract the magnitudes of individual coupling path by analyzing combined multi-path coupling. These coupling noises are then ranked based on their determined magnitudes to identify the primary coupling paths. Additionally, an improved isolation structure is introduced for the critical noise coupling path. The coupling noise can be suppressed by utilizing a layer-switching feedline structure. The interference level can be reduced by 18 dB, thereby lowering coupling noise to - 70 dB. This approach meets the noise requirements for radar sensors, and supports the optimized development of radar test boards.