{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T16:11:52Z","timestamp":1775837512360,"version":"3.50.1"},"reference-count":19,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2024,2,7]],"date-time":"2024-02-07T00:00:00Z","timestamp":1707264000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/summer-heart-0930.chufeiyun1688.workers.dev:443\/https\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation (NRF) of Korea","doi-asserted-by":"publisher","award":["2020R1A2C1008484"],"award-info":[{"award-number":["2020R1A2C1008484"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation (NRF) of Korea","doi-asserted-by":"publisher","award":["2022"],"award-info":[{"award-number":["2022"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Kwangwoon University Research","award":["2020R1A2C1008484"],"award-info":[{"award-number":["2020R1A2C1008484"]}]},{"name":"Kwangwoon University Research","award":["2022"],"award-info":[{"award-number":["2022"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A 28 GHz digitally controlled 6-bit phase shifter with a precision calibration technique in GaN high-electron mobility transistor (HEMT) technology is presented for Ka-band phased-array systems and applications. It comprises six stages, in which stages 1 and 2 for 5.625\u00b0 and 11.25\u00b0 are designed in the form of a switched-line circuit, and stages 3, 4, and 5 for 22.5\u00b0, 45\u00b0, and 90\u00b0 are designed in the form of a switched-filter circuit. The final stage 6 for 180\u00b0 is designed in a single-to-differential balun followed by a single-pole double-throw (SPDT) switch for achieving an efficient phase inversion. A novel continuous tuning calibration technique is proposed to improve the phase accuracy. It controls the gate bias voltage of off-state HEMTs at the stage 6 SPDT switch for fine calibration of the output phase. Fabricated in a 0.15 \u03bcm GaN HEMT process using a die size of 1.75 mm2, the circuit produces 64 phase states at 28 GHz with a 5.625\u00b0 step. The experimental results show that the Root-Mean-Square (RMS) phase error is significantly improved from 8.56\u00b0 before calibration to 1.08\u00b0 after calibration. It is also found that the calibration does not induce significant changes for other performances such as the insertion loss, RMS amplitude error, and input-referred P1dB. This work successfully demonstrates that the GaN technology can be applied to millimeter-wave high-power phased-array transceiver systems.<\/jats:p>","DOI":"10.3390\/s24041087","type":"journal-article","created":{"date-parts":[[2024,2,7]],"date-time":"2024-02-07T06:12:58Z","timestamp":1707286378000},"page":"1087","update-policy":"https:\/\/summer-heart-0930.chufeiyun1688.workers.dev:443\/https\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["A 28 GHz GaN 6-Bit Phase Shifter MMIC with Continuous Tuning Calibration Technique"],"prefix":"10.3390","volume":"24","author":[{"given":"Soyeon","family":"Seo","sequence":"first","affiliation":[{"name":"Department of Electronic Convergence Engineering, Kwangwoon University, Seoul 01897, Republic of Korea"}]},{"given":"Jinho","family":"Lee","sequence":"additional","affiliation":[{"name":"Now with Samsung Electronics Co., Suwon 16677, Republic of Korea"}]},{"ORCID":"https:\/\/summer-heart-0930.chufeiyun1688.workers.dev:443\/https\/orcid.org\/0009-0007-0276-9904","authenticated-orcid":false,"given":"Yongho","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Electronic Convergence Engineering, Kwangwoon University, Seoul 01897, Republic of Korea"}]},{"ORCID":"https:\/\/summer-heart-0930.chufeiyun1688.workers.dev:443\/https\/orcid.org\/0000-0003-1141-3428","authenticated-orcid":false,"given":"Hyunchol","family":"Shin","sequence":"additional","affiliation":[{"name":"Department of Electronic Convergence Engineering, Kwangwoon University, Seoul 01897, Republic of Korea"}]}],"member":"1968","published-online":{"date-parts":[[2024,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Lee, S., Lee, Y., and Shin, H. 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