Quasi-circulator for effective cancellation of transmitter leakage signals in monostatic six-port radar

Yang, Jong‐Ryul; Kim, Dong-Wook; Hong, Songcheol

doi:10.1049/el.2009.9062

Cited by 7 publications

(6 citation statements)

References 5 publications

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“…Substituting (5) into (11) for S 31 after modifying (5) for S 41 * , the magnitude of the Tx leakage isolation |S 31 | can be expressed as…”

Section: Design Of the Quasi-circulator Using The Asymmetric Couplermentioning

confidence: 99%

“…The planar quasi-circulator is a useful component in separating transmitting (Tx) and receiving (Rx) signals in miniaturized monostatic radar and communication systems that use a single antenna to transmit and receive wireless signals [4,8,9]. A branch-line coupler with a terminated port is conventionally used for a planar quasi-circulator because of its simple and low-cost design and its realization on a printed circuit board (PCB) [4,[8][9][10][11]. However, the low isolation of the branch-line coupler between the Tx and Rx paths, which lowers the Rx sensitivity or saturates the receiver, causes a receiver malfunction and limits the maximum detectable range [4,[8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…A branch-line coupler with a terminated port is conventionally used for a planar quasi-circulator because of its simple and low-cost design and its realization on a printed circuit board (PCB) [4,[8][9][10][11]. However, the low isolation of the branch-line coupler between the Tx and Rx paths, which lowers the Rx sensitivity or saturates the receiver, causes a receiver malfunction and limits the maximum detectable range [4,[8][9][10][11][12][13]. In previous studies, quasi-circulators using two branch-line couplers, a coupled-line directional coupler and a directional coupler with a flat coupling were developed as the planar quasi-circulator to improve the isolation [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…However, the low isolation of the branch-line coupler between the Tx and Rx paths, which lowers the Rx sensitivity or saturates the receiver, causes a receiver malfunction and limits the maximum detectable range [4,[8][9][10][11][12][13]. In previous studies, quasi-circulators using two branch-line couplers, a coupled-line directional coupler and a directional coupler with a flat coupling were developed as the planar quasi-circulator to improve the isolation [9][10][11][12]. The isolation between the Tx and Rx ports increased considerably in previous circulators; however, their size also increased because of the additional components.…”

Section: Introductionmentioning

confidence: 99%

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Quasi-Circulator Using an Asymmetric Coupler for Tx Leakage Cancellation

2018

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A quasi-circulator is proposed by using an asymmetric coupler with high isolation between the transmitting (Tx) and receiving (Rx) ports. The proposed quasi-circulator consists of quarter-wave transmission lines, which have unbalanced characteristic impedances and the terminated port, which is purposely unmatched with the reference impedance in the coupler. The port compensates for the asymmetric impedances of the coupler using the proposed design parameter. Because of its asymmetric structure and the usage of the unmatched port, the proposed circulator can be accurately designed to have high Tx–Rx isolation without increasing the signal losses in the Tx and Rx paths at the operating frequency. The proposed quasi-circulators show isolation improvements of 9.07 dB at 2.45 GHz and 7.95 dB at 24.125 GHz compared with conventional circulators using the symmetric couplers. The characteristic improvement of the proposed quasi-circulator was demonstrated by the increase of the detectable range of the 2.45 GHz Doppler radar sensor with the quasi-circulator.

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“…Substituting (5) into (11) for S 31 after modifying (5) for S 41 * , the magnitude of the Tx leakage isolation |S 31 | can be expressed as…”

Section: Design Of the Quasi-circulator Using The Asymmetric Couplermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quasi-Circulator Using an Asymmetric Coupler for Tx Leakage Cancellation

2018

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“…to consider both the isolation issue and the antenna feed reflection to compensate for each other, or to use the static reflection as a bias signal for the detectors to equalize the gain imbalance within the Six-Port junction. Simplified systems, e.g., [12] or [13], based on the same feed-forward idea are already studied and measured but only capable of compensating the isolation P iso .…”

Section: Six-portmentioning

confidence: 99%

Distance measurements and limitations based on guided wave 24 GHz dual tone Six-port radar

Lindner

Barbon

Linz

et al. 2015

Int. J. Microw. Wireless Technol.

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In the following, a continuous wave radar system based on the Six-port principle will be shown for measurement tasks at enclosed systems needing micrometer accuracy as well as high update rates like tank level monitoring or hydraulic cylinder piston control. To exceed the ambiguity limit of such an interferometric system, a dual tone approach is used. The system will be presented with measurement results at 24 GHz within a WR42 waveguide to prove the feasibility of the proposed concept. Furthermore, considerations on timing will show the potential as a low-latency system, capable of high measurement data update rates, and different influences on the system performance and limitations of such a system will be discussed in comparison to alternative setups.

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Monostatic continuous-wave radar integrating a tunable wideband leakage canceler for indoor tagless localization

Mercuri

Barmuta

Soh

et al. 2017

Int. J. Microw. Wireless Technol.

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Continuous-wave (CW) radars have been recently investigated in healthcare aiming at contactless health monitoring. However, a major problem in monostatic CW architectures is represented by the unwanted leakage produced by poor isolation between transmitter and receiver, which can drastically decrease the receiver's sensitivity reducing therefore the radar dynamic range. Although this situation can be easily controlled in case of narrowband CW radar by an appropriate passive microwave design, it becomes much more complicated in case of stepped-frequency CW and frequency-modulated CW architectures that present an ultra-wideband nature. In this paper, a monostatic CW radar integrating a tunable wideband leakage canceler aiming at indoor tagless localization is presented and discussed. The use of the feedforward canceler allows a strong reduction of the unwanted leakage over the whole radar bandwidth. Experimental results demonstrate the feasibility of this approach, showing an outstanding improvement of the radar dynamic range.

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Quasi-circulator for effective cancellation of transmitter leakage signals in monostatic six-port radar

Cited by 7 publications

References 5 publications

Quasi-Circulator Using an Asymmetric Coupler for Tx Leakage Cancellation

Quasi-Circulator Using an Asymmetric Coupler for Tx Leakage Cancellation

Distance measurements and limitations based on guided wave 24 GHz dual tone Six-port radar

Monostatic continuous-wave radar integrating a tunable wideband leakage canceler for indoor tagless localization

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