應用於手持裝置之小型化雙寬頻雙極化之5G毫米波天線陣列設計

Abstract

本論文提出一款專為第五代行動通訊(5G)行動終端應用所設計的小型化雙寬頻雙極化毫米波天線陣列。為滿足5G新無線電（New Radio）技術中n257/n258/n261（24.25–29.5 GHz）與n259/n260（37–43.5 GHz）頻段的嚴格規格要求，本設計實現了寬阻抗頻寬（以|S₁₁| < –6 dB為準）、高極化隔離度（>15 dB）、以及分別在低頻與高頻超過9 dBi與10 dBi的峰值增益，同時保持極為精巧的體積設計，充分符合智慧型手機的空間限制，並有效因應毫米波通訊中常見的自由空間傳輸損耗與遮蔽問題。 本設計採用多層堆疊式貼片架構，使用中高介電常數的RO3006與RO4460G2高頻基板，並依循「子單元—單元—陣列」的系統化設計流程。於子單元階段，分別針對低頻（LB）與高頻（HB）堆疊貼片天線子單元進行尺寸最佳化，實現寬頻阻抗匹配與雙線性極化。於單元階段，整合LB與HB天線子單元為一體，並系統性分析十二種金屬層堆疊方式與四種饋入組合。結果顯示，採用邊緣饋入的LB子單元與角落饋入的HB子單元，配合選用適當的金屬層，能兼顧良好阻抗匹配與極化隔離度。 在陣列設計方面，以最佳化天線單元構成1×4線性陣列，尺寸僅3.5 mm × 22 mm × 0.75 mm。模擬結果證實所設計的陣列具備優異的增益與隔離度表現，且在與波束碼簿結合後，亦展現優異的波束覆蓋能力與寬頻特性。為驗證陣列設計之模擬準確性與實際製作可行性，我們進一步設計一款整合一分四功率分配器之陣列樣品進行量測。模擬與實測結果在S參數、場型與增益方面高度吻合，證明陣列設計模擬效能的準確性與製程可行性。 綜合而言，本論文所提出之毫米波天線陣列成功兼顧小型化、雙頻支援、極化多樣性與製程相容性，為5G行動裝置提供一項具備高度實用價值的毫米波天線解決方案，具備與波束成形晶片整合的潛力，極具商業應用前景。

In this thesis, a compact, dual-broadband, dual-polarization millimeter-wave (mmWave) antenna array is proposed for the 5th-generation mobile communication technology (5G) mobile terminal applications. To meet the stringent demands of 5G New Radio specifications—particularly within the n257/n258/n261 (24.25–29.5 GHz) and n259/n260 (37–43.5 GHz) bands—the proposed antenna design achieves wide impedance bandwidth (under an |S₁₁| < –6 dB criterion), high polarization isolation (>15 dB), and peak gains exceeding 9 dBi and 10 dBi in the respective bands, all within a highly miniaturized footprint. These features ensure compatibility with space-constrained smartphones while addressing critical mmWave propagation challenges such as path loss and signal blockage. To achieve these goals, a multilayer stacked-patch architecture is adopted, implemented on intermediate-permittivity RO3006/RO4460G2 substrates. The design process follows a structured “sub-element-to-element-to-array” methodology. At the sub-element level, separate low-band (LB) and high-band (HB) stacked patches are dimensionally optimized for wideband impedance matching and dual-linear polarization. In the element stage, these patches are integrated into a single dual-broadband module, with systematic studies evaluating twelve metal-layer stacking schemes and four feed combinations. Results reveal that a hybrid configuration using an edge-fed LB sub-element and corner-fed HB sub-element with a properly chosen combination of metal layers offers superior impedance and isolation performance. At the array level, the optimized antenna element is configured into a 1×4 linear array measuring only 3.5 mm × 22 mm × 0.75 mm. Simulated results confirm robust gain and isolation, while beam-codebook-based evaluations further demonstrate its beamforming capability and broadband characteristics. For experimental validation, a measurement-friendly version of the array—integrated with a 1-to-4 power divider—is fabricated and characterized. Measured results closely match simulations across S-parameters, radiation patterns, and gain, thereby verifying the simulation model’s accuracy and fabrication feasibility. In conclusion, this work establishes a high-performance, integration-ready antenna solution suitable for commercial 5G handheld devices. The proposed array successfully balances size, dual-broadband support, polarization diversity, and manufacturability, paving the way for practical mmWave front-end integration with beamforming ICs in next-generation mobile platforms.