本論文將會針對地波雷達於傳播路徑上的模態不匹配與接收端所產生的破壞性干 涉此兩大議題提出一種全新的雷達部署方法。其部署方式的關鍵就在於把激發源的位置 從地面上改由從地底激發，並透過以類表面電漿結構作為模態過渡的橋樑，將其放置於 地波雷達天線的上方且與海水相鄰，使其不同頻段產生的類表面電漿模態電場分布與地 波相似，幫助地波雷達天線輻射能量耦合(即為能量轉移)成地波進而提高激發地波的效 率。此外，為了驗證在不同頻段產生與地波相似的類表面電漿模態電場分布，本論文使 用本徵模態法與多層同/異向性之週期性結構反射/透射法進行模態分析。 本論文的激發源分為兩種，半波長偶極天線陣列以及洩漏波天線，因此第二章也會 論述各自的設計方法與流程，並將經基因演算法設計後的洩漏波天線與傳統串列式饋入 貼片天線相比較，並在設計時間與主波束角偏移的部分取得一些優勢。第三章則是整個 地波雷達場景的模擬與量測結果，並且透過量測結果得知本論文提出的雷達部署方法確 實可行，在量測的頻段(8GHz-17GHz)中達到地波增強的效果，並且具有 66%的相對頻 寬，可涵蓋現有的地波雷達頻段並實際應用。 ;This thesis presents a novel radar deployment method aimed at addressing two major issues in ground wave radar : modal mismatch along the propagation path and the destructive interference generated at the receiving end. The key to this deployment approach lies in relocating the excitation source from the ground surface to the subterranean level. By employing a metallic, expandable periodic structure as a bridge for modal transition, this excitation source is placed above the ground wave radar antenna, adjacent to seawater. This placement results in the generation of surface plasmon mode field distributions in different frequency bands that resemble ground waves, assisting in the efficient coupling and transfer of radiation energy from the ground wave radar antenna into ground waves, thereby enhancing the efficiency of exciting ground waves.Additionally, to verify the generation of surface plasmon mode field distributions similar to ground waves in different frequency bands, this thesis utilizes the eigenmode method and the reflection/transmission method of multi-layer periodic structures with both isotropic and anisotropic properties for modal analysis. III The excitation sources in this thesis are divided into two types: half-wavelength dipole antenna arrays and leaky wave antennas. Therefore, Chapter 2 also discusses their respective design methods and processes. A comparison is made between the leaky wave antenna designed using a genetic algorithm and traditional serial-fed patch antennas, highlighting advantages in design time and main beam angle offset.Chapter 3 focuses on the simulation and measurement results of the entire ground wave radar scenario. Through these results, it is confirmed that the radar deployment method proposed in this thesis is indeed feasible. It achieves ground wave enhancement in the measured frequency range (8GHz-17GHz) and possesses a relative bandwidth of 66%. This bandwidth covers existing ground wave radar frequency bands and is suitable for practical applications.
