| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 104 === A novel single-band integration of dual-mode retrodirective/beam-switching phased array is proposed in this thesis. Different form previous dual-band ones, the proposed system is capable of functioning as a reflection-type retrodirective array or beam-switching array at a single frequency. By incorporating varactors into the feeding network, the two array systems can be integrated as a whole at a common frequency by simply controlling the bias voltage.
The key innovation to fulfill the design is the reconfigurable synthesized line, whose transmission characteristics are controlled by a varactor diode. The synthesized line comprises quasi-lumped line inductor, parallel-plate capacitor and an LC resonator. The varactor diode is embedded in the LC tank for reconfigurability. By properly selecting the bias voltage of the varactor, the LC resonator functions as either an equivalent capacitor to establish a transmission path, or a virtual short circuit to make a part of the network become completely invisible to the signal flow.
By utilizing the reconfigurable synthesized line, core components including the single-band dual-mode branch-line coupler, single-band dual-mode crossover and SPDT switch are successfully developed. The single-band dual-mode array, realized by integrating couplers with auxiliary components, is validated by experiments.
Furthermore, the aforementioned phased array is directly integrated with binary and quadrature phase shift keying (BPSK/QPSK) modulators to prove the feasibility of data transmission when operated as the retrodirective array.
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