Tunable Quasi-Circulator Based on a Compact Fully-Reconfigurable 180° Hybrid for Full-Duplex Transceivers

Deng, Zhixian; Qian, Huizhen Jenny; Luo, Xun

doi:10.1109/tcsi.2019.2905877

Cited by 12 publications

(8 citation statements)

References 33 publications

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“…The control voltage V C is fed by a 10-k resistor R B . It is worth pointing out that there is a trade-off between the tuning range and quality factor of the C t [25]. Then, an optimized C D = 0.6 pF (i.e., GRM1555 series capacitors from Murata, with Q D = 124 at 2.35 GHz) is chosen for the tunable C t implementation.…”

Section: B Cg-stage and Cs-stagementioning

confidence: 99%

“…Note that since the impedance tuner is unavailable, the loaded impedance at ANT Port is varied by the different combinations of resistors, inductors, and capacitors. The TX-RX isolation under different ANT VSWR can be improved by introducing an ANT impedance balancer or tuner [20], [25]. The SCAL 70CTR3 is used for RX NF measurement under different temperatures.…”

Section: Fabrication and Measurementmentioning

confidence: 99%

“…Nevertheless, the requirement of the additional modulated LO signals increases the system complexity. Recently, QCs using the combined active and passive circuits are developed with advantages of design flexibility and good performance [21]- [25]. As shown in Fig.…”

mentioning

confidence: 99%

“…As shown in Fig. 1(a), a tunable QC using the compact fully reconfigurable 180 • hybrid and amplifier stages is proposed to improve the isolation performance [25]. However, such a combined-type of QC suffers from the fundamental 3-dB path loss introduced by the reciprocal passive devices, while the operation frequency range still needs to be further expanded.…”

mentioning

confidence: 99%

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Low NF and High P1dB Wideband Quasi-Circulator With Unequal Power Split and Reconfigurable Inter-Stage Matching

Chen

Deng

Shu

et al. 2021

IEEE Trans. Microwave Theory Techn.

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In this article, a wideband quasi-circulator (QC) with the low noise figure (NF) and high 1-dB compression point (P 1 dB ) is proposed. The slotline-based 180 • hybrid is introduced to achieve the wideband high transmitter-receiver (TX-RX) isolation. Meanwhile, the bidirectional in-phase stage and the nonreciprocal out-of-phase stage are utilized to obtain specific power-split ratios for the low insertion loss and high antenna-transmitter (ANT-TX) isolation. By using the unequal power split, the proposed QC is without the fundamental 3-dB loss seen in reciprocal ANT interfaces. Besides, to further enhance the TX-RX isolation within a wideband, a reconfigurable inter-stage matching network based on a varactor-tuned capacitor is implemented. To verify the mechanisms mentioned above, a reconfigurable wideband QC operating at 1.75-2.9 GHz is implemented and fabricated. The total power consumption is 224 mW. The measurement exhibits in-band TX-RX isolation of 27-58 dB. The TX-ANT and ANT-RX insertion losses are 4.3-5.0 dB and 1.0-1.9 dB, respectively. The QC also achieves the minimum in-band ANT-RX NF of 3.4 dB. Meanwhile, the measured TX-ANT and ANT-RX IIP3s are 39.4 and 32.5 dBm, respectively. The TX input P 1 dB is greater than 28.78 dBm, while the RX input P 1 dB is 23 dBm. The TX-induced ANT-RX P 1 dB is measured to be 28 dBm. Index Terms-180 • hybrid full-duplex (FD), quasi-circulator (QC), reconfigurable circuits, wideband. I. INTRODUCTIONW ITH the ever-increasing demand for high data rates in modern wireless communications, there are urgent requirements of wireless channels with large capacity and high spectral efficiency in recent years. To satisfy the practical requirements, either time or frequency division duplexing systems are employed [1], [2]. However, all these systems are exclusively half-duplex, which limits the maximum transmission rate to only half of the network capacity. For this reason, the full-duplex (FD) system is introduced to double the Manuscript

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Section: B Cg-stage and Cs-stagementioning

confidence: 99%

Section: Fabrication and Measurementmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Low NF and High P1dB Wideband Quasi-Circulator With Unequal Power Split and Reconfigurable Inter-Stage Matching

Chen

Deng

Shu

et al. 2021

IEEE Trans. Microwave Theory Techn.

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“…In addition, the circulators in [25] and [29], [ [30] exhibit poor linearity with the their 1-dB compression point (P1dB) being less than -2 dBm. The circulator in [45] demonstrates good linearity, however it isn't IC integrated and only covers frequencies up to 3.56 GHz.…”

Section: Introductionmentioning

confidence: 99%

MMIC GaAs Isolators and Quasi-Circulators With Co-Designed RF Filtering Functionality

Ashley

Psychogiou

2023

IEEE J. Microw.

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This paper reports on the RF design and practical development of GaAs MMIC multi-functional RF isolators and quasi-circulators with embedded filtering functionality. They are based on cascaded arrays of non-reciprocal resonators (NRRs), passive resonators, and impedance inverters. A unique transistor-based architecture is used for the realization of the NRR that exhibits an one-pole type bandpass response in the forward direction and RF signal cancellation in the reversed one. By controlling the number and type of resonators within cascaded resonator arrays, different levels of gain, out-of-band selectivity and in-band isolation can be obtained. The operating principles of the multi-functional isolator/filtering and quasi-circulator/filtering concepts are presented through synthesized and linear circuit-simulated examples. Practical design aspects using a commercially available GaAs MMIC process are also discussed. For proofof-concept demonstration purposes, four prototypes were designed and experimentally validated at X-band. They include: i) a NRR, ii) a two-resonator based frequency selective isolator (FSI), iii) a five-resonator based FSI, and iv) a two-pole/two-TZ frequency selective quasi-circulator (FSQC).

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Design of a 60 GHz Active Quasi-Circulator in 22nm FDSOI Process

Chowdhury

Hasan

2023

2023 IEEE 16th Dallas Circuits and Systems Conference (DCAS)

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Tunable Quasi-Circulator Based on a Compact Fully-Reconfigurable 180° Hybrid for Full-Duplex Transceivers

Cited by 12 publications

References 33 publications

Low NF and High P1dB Wideband Quasi-Circulator With Unequal Power Split and Reconfigurable Inter-Stage Matching

Low NF and High P1dB Wideband Quasi-Circulator With Unequal Power Split and Reconfigurable Inter-Stage Matching

MMIC GaAs Isolators and Quasi-Circulators With Co-Designed RF Filtering Functionality

Design of a 60 GHz Active Quasi-Circulator in 22nm FDSOI Process

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