Directional Coupler With Good Restraint Outside the Passband and Its Frequency-Agile Application

Cheng, Yu Jian; Wang, Lei; Wu, Jie; Yang, Fan

doi:10.2528/pier12121009

Cited by 6 publications

(5 citation statements)

References 14 publications

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“…Branch line hybrid couplers are prominently used in the design of many microwave circuits (e.g., data modulators, phase shifters, balanced amplifiers and feeding networks). Most of the research on this structure focuses on achieving circuit miniaturization and bandwidth plus isolation enhancement through different techniques, including left-handed transmission lines [1], via-holes [2,3], air-gaps [4], stubs [5,6], coupled [7,8] and π-shaped lines [9].…”

Section: Introductionmentioning

confidence: 99%

Complex Impedance Transformers Based on Branch-Line Hybrid Couplers

Alcon¹,

Lopez²,

Herrán³

et al. 2016

PIER C

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A topology, equations and design methodology for complex impedance-transforming branch-line hybrid couplers are presented. This method also allows the realization of real impedancetransforming to higher impedances. Limitations for real, imaginary and complex impedances are discussed. Test results are shown for a 3 dB 50 to 450 Ω hybrid coupler, at a 2 GHz center frequency, with a 21% bandwidth, an amplitude balance of 4.35 ± 1 dB and a phase balance of 92.16 • ± 8.8 •. To showcase the complex impedance scenario, two 3 dB 50 Ω to 70 − 200j Ω are measured at a 2 GHz center frequency. One of these couplers uses a technique for reducing the chip size, yielding a 22.5% bandwidth, 4 ± 0.9 dB amplitude balance and 93.22 • ± 6.74 • phase balance, while accomplishing a 25% size reduction.

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Section: Introductionmentioning

confidence: 99%

Complex Impedance Transformers Based on Branch-Line Hybrid Couplers

Alcon¹,

Lopez²,

Herrán³

et al. 2016

PIER C

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“…In addition, for removing additional impedance transformer and decreasing circuit size and cost, asymmetric branch-line couplers terminated by arbitrary impedances were reported in [11,12], and arbitrary phase-difference coupler was presented in [13,14]. Furthermore, with using the open-ended coupled lines instead of branch lines and port feeding lines, filter-couplers were proposed in literatures [15,16], respectively.…”

Section: Introductionmentioning

confidence: 99%

“…The original branch-line coupler [1] operates only at single band and suffers from disadvantages of narrow bandwidth. In the past decades, there have been many literatures about several new properties of branchline coupler for miniaturizing the circuit sizes and cutting down the cost, such as dual-or multi-band operations [2][3][4][5][6][7][8], arbitrary coupling levels [9,10], inherent transforming [11,12], arbitrary output phase difference [13,14], and co-design with filter [15,16]. For the dualband branch-line couplers, approaches based on the introduction of the suitable stub lines in a standard branch-line coupler structure [2][3][4], adopting composite right/left-handed transmission line structures [5], and inserting a transmission line section at the input ports [6] have been proposed.…”

Section: Introductionmentioning

confidence: 99%

Generalized Impedance-Transforming Dual-Band Branch-Line Couplers for Arbitrary Coupling Levels

Liu¹,

Liu²,

Wu³

et al. 2013

PIER B

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Abstract-High-performance dual-band Doherty power amplifier and non-uniform circularly polarized antenna array require impedancetransforming unequal dual-band 90 • branch-line couplers for power dividing and phase shifting in the feed networks. In this paper, an analytical design methodology of generalized impedance-transforming dual-band branch-line couplers for arbitrary coupling levels is proposed. The coupler features wide range of realizable frequency ratio, multiple flexible selections of open-or short-circuited and pi-or T-network topologies. For demonstration, four numerical examples with different parameters are presented. Furthermore, two microstrip couplers based on open-circuited pi-and T-network topologies were fabricated and measured. The measured results show good performance at dual 1.8/3.45 GHz bands. The fractional bandwidths defined by the fluctuation of the coupling level and the phase difference less than ±0.5 dB and ±5 • are up to 17% and 18%, 18% and 2% for open-circuited pi-and T-network topologies, respectively.

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“…As couplers are generally designed based on the electrical length of a desired fundamental signal, higher order harmonic signals from those nonlinear devices will degrade the quantity of the desired signal. To suppress those unwanted harmonic signals, external low-pass filters are needed [5,6]. However, such filters increase circuit size and insertion loss.…”

Section: Introductionmentioning

confidence: 99%

Bandwidth Improvement of a Compact Quadrature Hybrid Coupler With Harmonic Rejection Using Lumped Elements

Li²,

Gu³

et al. 2013

PIER C

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Abstract-A compact quadrature hybrid coupler with harmonic suppression using lumped-element band-stop resonator is proposed for bandwidth improvement. Conventionally, harmonic rejection is realized by three band-stop resonators in lumped hybrids. The using of three band-stop resonators realizes better harmonic suppression while exhibiting narrower frequency response. So as to improve operation bandwidth behavior, the number of band-stop resonator applied in the proposed topology is minimized to one. Trading off with acceptable reduction in harmonic rejection, the proposed hybrid enlarges working bandwidth with fewer numbers of lumped devices. Detailed design and theoretical analysis are presented and the expressions of lumped elements with dependence of rejected frequency are obtained. To validate the analysis, three 2.45 GHz couplers are fabricated on an FR-4 printed circuit board. The experimental results exhibit 27.3%, 26.9% and 23.3% operation bandwidth with better than 16 dB, 17 dB, and 21 dB harmonic suppressions at 4.9 GHz, 6.1 GHz, and 7.35 GHz, respectively. Less than 0.8 dB amplitude imbalance and 2 • phase error are achieved for all the three couplers, which are matched well with theoretical analysis.

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Directional Coupler With Good Restraint Outside the Passband and Its Frequency-Agile Application

Cited by 6 publications

References 14 publications

Complex Impedance Transformers Based on Branch-Line Hybrid Couplers

Complex Impedance Transformers Based on Branch-Line Hybrid Couplers

Generalized Impedance-Transforming Dual-Band Branch-Line Couplers for Arbitrary Coupling Levels

Bandwidth Improvement of a Compact Quadrature Hybrid Coupler With Harmonic Rejection Using Lumped Elements

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