此論文主要在於設計無線功率傳輸(Wireless power transfer)系統的無線功率傳
輸介面與接收端前端。在植入式電子設備的生醫應用中，磁耦合式無線傳輸介面
的感應線圈不論在功率傳輸效率(Power transfer efficiency)或功率傳輸能力(Power transfer capability)都有非常關鍵的影響。因此我們在實際應用時的空間限制下，基於最大化功率效率的目標，以我們的設計程序來最佳化感應線圈。根據此組線圈在耦合係數(k)變異時對線圈負載的輸出功率分布，以改變整流器的輸入阻抗原
理，設計三種不同模式的整流器，藉此提升耦合係數變異下的輸出功率，進一步
達到在足夠的輸出功率條件下，能涵蓋更大範圍的耦合係數變異。
我們設計與實作在0.18微米互補式金屬氧化物半導體製程，操作於13.56百
萬赫茲的頻率。量測結果顯示整體效率在標準的耦合係數與重載100歐姆的條
件下達到50.3%。對於足夠的輸出功率條件，三種模式的整流器使k的範圍延伸
到0.092與0.02。相較於只有一種模式的整流器，在不調整傳輸端操作的前提下，
輸出功率的k範圍可提升0.021，且在k等於0.073時負載範圍延伸到80Ω。

A wireless power transfer system (WPT) system focused on wireless transmission interface and receiver front end is presented in this work. In our target application for implantable medical devices (IMDs), the weakly-coupled interface of resonant coupling WPT is the most critical block for two most important index: power transfer
efficiency (PTE) and power transfer capability (PTC). In the proposed design, we optimize the geometric parameters of coupling coils through a reasonable procedure based on efficiency of coupling coils under practical IMDs spatial constraints. According to the output power distribution of the designed coils with respect to load, the proposed 3-mode rectifier is used to improve PTC and ensure sufficient output power for wider coupling variation. Active-diode topology is adopted for rectifier for maximizing efficiency under milliwatt power level.
The WPT system operating at 13.56MHz includes off-chip resonant capacitors and coupling coils, fabricated in printed circuit boards (PCBs) and an on-chip 3-mode rectifier implemented in a 0.18 μm CMOS process. Measurement results shows that efficiency of total system from input of coupling coils to load of rectifier reaches 50.3% at k=0.073 and heavy load of 100 Ω. With proposed 3-mode rectifier, output DC power increases in both mode 2 and mode 3 for larger and smaller than k=0.073, respectively. Without adjusting the operation in transmitter, coupling factor extends to 0.092 and 0.02 for sufficient output power 14.4mW with 0.021 of k range improvement and load range extend to 80 Ω at k=0.073, compared with conventional receiver design with only one mode.

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