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Abstract We report a novel approach for realizing tunable/reconfigurable terahertz (THz) mesh filters on the basis of micromachined mesa‐array structures. In this approach, different filter patterns are generated virtually using photogenerated free carriers in a semiconducting mesa‐array structure to achieve superior tunability and reconfigurability. Micromachined mesa‐array structures enable the formation of high fidelity, optically generated mesh filter structures for THz frequencies. To evaluate the proposed filter designs, the optically patterned spatial modulation properties of mesa‐array structures were first evaluated. Reconfigurable mesh filter prototypes were then designed and simulated using silicon mesa arrays with 50 × 50 μm2square mesa unit cells. Simulations show that reconfigurable bandpass filters (BPFs) operating in the frequency range of 108–489 GHz with insertion losses of 0.82–1.13 dB can be achieved. By employing smaller unit cells, the frequency tuning range and filtering performance can be further improved. In addition to BPFs, other filter functionalities can also be realized utilizing the proposed approach. The wide tuning range and reconfigurability of the mesh filters demonstrate that the proposed approach is promising for developing tunable/reconfigurable circuits and components for advanced THz sensing, imaging, and communications.
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An S-band Automatically Tunable Bandpass Filter Based on a Machine Learning Approach
This paper presents a novel automatic tuning mechanism that eliminates hand-tuning and is suitable for electronically-tunable microwave filters. The proposed method is based on a deep Q-learning approach using physics-based filter characteristic parameters like resonant frequency, bandwidth, insertion loss, and return loss. The whole tuning process is done automatically and does not require any pre-tuning or human expertise. Furthermore, unlike single-frequency post-production tuning techniques, the presented methodology is applicable to continuously-tunable filters covering a wide frequency range. This method is experimentally demonstrated on a 2-3.5 GHz evanescent-mode electronically-tunable bandpass filter. To the best of our knowledge, this is the first demonstration of such an automatic tuning mechanism where the user can specify any frequency of interest and the filter tunes automatically to that frequency within the entire operating range of the filter.
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- PAR ID:
- 10323556
- Date Published:
- Journal Name:
- 2021 IEEE 21st Annual Wireless and Microwave Technology Conference (WAMICON)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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