A review of hybrid couplers: State-of-the-art, applications, design issues and challenges
01 Aug 2021-International Journal of Numerical Modelling-electronic Networks Devices and Fields (John Wiley & Sons, Ltd)-Vol. 34, Iss: 5
TL;DR: Several techniques for hybrid coupler to achieve the required bandwidth and size reduction are highlighted, such as the T‐shape, meander line, two sections, three‐section, and parallel couple lines.
About: This article is published in International Journal of Numerical Modelling-electronic Networks Devices and Fields.The article was published on 2021-08-01. It has received 11 citations till now.
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Proceedings Article•
01 Jan 2004
TL;DR: In this paper, space filling curves have been used to realize a family of miniaturized hybrid couplers, and the performance of the proposed space-filling hybrids is as good as that of the corresponding conventional structures, and even better in some cases.
Abstract: In this paper, space-filling curves have been used to realize a family of miniaturized hybrids. The large surface area occupied by a conventional structure has been significantly reduced through the use of space-filling curves having the same electrical characteristics. Several space-filling curves have been studied and implemented in different designs. The second-iteration Moore rat-race coupler occupies only 12.6% of the conventional coupler's area, while the area of the second-iteration Sierpinski branch-line coupler is 24.7% of the conventional case. On the other hand, a nine-section Minkowski coupled-line balun is confined in 60% of the conventional balun's area. However, the effective size reduction depends on the used space-filling curve, compression ratio, and associated coupling between segments. The performance of the proposed space-filling hybrids is as good as that of the corresponding conventional structures, and even better in some cases. The design and simulation of the proposed space-filling hybrids have been performed using a moment-method-based full-wave electromagnetic simulator. Measurements of one fabricated coupler prototype are in good agreement with simulation results.
13 citations
TL;DR: In this paper , a beam steerable antenna array using a 4 × 4 Butler Matrix feed network technique is developed to operate at the X band frequency range, where the main beam pattern of the antenna array is switched between four directions (+10°, −38°, +38° and −10°).
Abstract: This article proposes the design, simulation, fabrication and testing of a beam steerable antenna array using a 4 × 4 Butler Matrix feed network technique. The proposed antenna is developed to operate at the X band frequency range. The integrated antenna array and the Butler Matrix feed network operating at 10 GHz has a bandwidth of approximately 2 GHz with an achieved gain of 12 dBi. The main beam pattern of the antenna array is switched between four directions (+10°, −38°, +38°, −10°) providing an effective coverage of over 100°. The proposed antenna has the advantages of low cost, easy fabrication, and simplicity.
4 citations
TL;DR: In this paper , a coplanar waveguide (CPW)-fed patch antenna is fabricated on a layer of metasurface to increase gain, and the antenna is fabrication on a Roger substrate with a thickness of 0.25mm.
Abstract: In this paper, a coplanar waveguide (CPW)-fed patch antenna is fabricated on a layer of metasurface to increase gain. The antenna is fabrication on Roger substrate with a thickness of 0.25 mm, with the overall dimension of the proposed design being 45 × 30 × 0.25 mm3. The size of the patch antenna is 24 × 14 × 0.25 mm3, and the AMC unit cell is 22 × 22 × 0.25 mm3. This metasurface is designed based on the split-ring resonator unit cells forming an array of the artificial magnetic conductor (AMC). Meanwhile, the antenna operation on 3.5 GHz is enabled by etching a split-ring resonator slot on the ground plane with a small gap to enhance antenna gain and improve impedance bandwidth when integrated with a metasurface. This simulation planer monopole antenna is applied for 5G application. The experimenter test is applied for the antenna performance in terms of return loss, gain, and radiation patterns. The operating frequency range with and without MTM is from 3.41 to 3.68 GHz (270 MHz) and 3.37 to 3.55 GHz (180 MHz), respectively, with gain improvements of about 2.7 dB (without MTM) to 6.0 dB (with MTM) at 3.5 GHz. The maximum improvement of the gain is about 42% when integrated with the AMC. The AMC has solved several issues to overcome the typical limitation in conventional antenna design. A circuit model is also proposed to simplify the estimation of the performance of this antenna at the desired frequency band. The proposed design is simulated by CST microwave studio. Finally, the antenna is fabricated and measured. Result comparison between simulations and measurements indicates a good agreement between them.
3 citations
DOI•
TL;DR: In this paper , the authors presented a novel Butler matrix implemented in the grounded co-planar waveguide (GCPW) technology, compactly integrated with a highly efficient and broadband air-filled substrate integrated waveguide cavity-backed patch antenna array (AA), giving rise to a broad operational frequency range covering the n257, n258, and n261 fifth-generation (5G) bands.
Abstract: This article presents a novel $4\times 4$ Butler matrix implemented in the grounded co-planar waveguide (GCPW) technology, compactly integrated with a highly efficient and broadband $1\times 4$ air-filled substrate integrated waveguide (AFSIW) cavity-backed patch antenna array (AA), giving rise to a broad operational frequency range [23.75, 31 GHz] (26.5%) covering the n257, n258, and n261 fifth-generation (5G) bands. Three novel quadrature hybrid couplers and two crossovers are designed and compared to obtain the optimal building blocks for the Butler matrix. Within each of the supported 5G bands, the measured excess insertion loss of the optimized Butler matrix remains smaller than 3.5dB with a maximal amplitude imbalance of ±0.9dB. Isolation between input ports is higher than 16.4dB. A maximal measured realized gain of 12.3dBi is obtained for the Butler matrix with integrated $1\times 4$ AA while ensuring a −3-dB beamwidth coverage of 110°. The main beamsteering directions of [−40°, −14°, 14°, 40°] exhibit measured deviations that stay within ±3°. The fabricated Butler matrix with AA features a very compact footprint of 21.4 mm $\times$ 46.0 mm $\times $ 2 mm [ $2\lambda _{0} \times 4.3\lambda _{0} \times 0.2\lambda _{0}$ ].
2 citations
TL;DR: The Editorial Board is modified by adding track editors between the EiC and the AEs, and the track editors now make the final decisions on all papers, and this allows theEiC to pay more attention to how well the Letters is performing in terms of time from submission to publication.
Abstract: I have had the privilege of serving as the Editor-in-Chief (EiC) for IEEE Microwave and Wireless Components Letters (MWCL) for the past three years. During this time, the Letters has experienced a 20% increase in the number of papers submitted and published. In addition, with the excellent work of associate editors (AEs) and reviewers, the impact factor has come back up to 2.17 for 2017. In order to handle this increased load, we have modified the Editorial Board by adding track editors between the EiC and the AEs. The track editors now make the final decisions on all papers, and this allows the EiC to pay more attention to how well the Letters is performing in terms of time from submission to publication.
1 citations
References
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Book•
01 Jun 2003
TL;DR: In this paper, the authors present a comprehensive treatment of lumped elements, which are playing a critical role in the development of the circuits that make these cost-effective systems possible, including inductors, capacitors, resistors, transformers, via holes, airbridges, and crossovers.
Abstract: Due to the unprecedented growth in wireless applications over the past decade, development of low-cost solutions for RF and microwave communication systems has become of great importance. This practical new book is the first comprehensive treatment of lumped elements, which are playing a critical role in the development of the circuits that make these cost-effective systems possible. The books offers you an in-depth understanding of the different types of RF and microwave circuit elements, including inductors, capacitors, resistors, transformers, via holes, airbridges, and crossovers. Supported with over 220 equations and more than 200 illustrations, it covers the practical aspects of each element in exceptional detail. No other single volume treats this subject matter in such depth. From materials, fabrication, and analyses - to design, modeling, and physical, electrical, and thermal applications, this unique resource offers you complete coverage of the critical topics you need understand for your work in the field. Offering the most comprehensive, up-to-date body of knowledge on lumped elements, the book is an indispensable professional reference and serves as an excellent text for senior undergraduate and graduate-level courses in RF and microwave circuit design.
840 citations
"A review of hybrid couplers: State-..." refers methods in this paper
...They are designed using directly connected circuit elements and are usually implemented by using either a distributed circuit element approach or by equivalent lumped elements.(34) Figure 3 shows the geometry of the conventional hybrid branchline coupler....
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Book•
01 Jan 1999
TL;DR: In this paper, the authors present a theoretical analysis of planar transmission lines with parallel-coupled TEM Directional Couplers and tight couplers, as well as Coupled-Line Filter Fundamentals.
Abstract: Introduction. Microwave Network Theory. Characteristics of Planar Transmission Lines. Analysis of Uniformerly Coupled Lines. Broadband Forward-Wave Directional Couplers. Parallel-Coupled TEM Directional Couplers. Nonuniform Broadband TEM Directional Couplers. Tight Couplers. Coupled-Line Filter Fundamentals. Advanced Coupled-Line Filters. Filters for Advanced Materials and Technologies. Coupled-Line Circuit Components. Baluns.
624 citations
TL;DR: In this article, an analysis of four-arm symmetrical networks such as a branched directional double stub coupler or the hybrid ring (rat race) is presented, where the input wave is broken into an even and an odd mode and the vector amplitude out the various arms is computed from the sums or differences of the reflection or transmission coefficients for the two modes.
Abstract: An analysis of four-arm symmetrical networks such as a branched directional double stub coupler or the hybrid ring (rat race) is presented. The input wave is broken into an even and an odd mode and the vector amplitude out the various arms is computed from the sums or differences of the reflection or transmission coefficients for the two modes. A zero decibel directional coupler is described and its possible use as a duplexer is proposed. The design of multiple stub directional couplers for any degree of coupling is discussed. A method of computing the bandwidth of all these couplers is outlined, and the bandwidth curves, the power out the various arms with respect to frequency of the zero decibel coupler, are computed. A tabulation is made for six different 3 db couplers (even-power split) and their standing wave ratio, evenness of power split and isolation of the fourth arm as a function of frequency assuming perfect performance at the band center.
471 citations
"A review of hybrid couplers: State-..." refers background in this paper
...To analyze the four-port symmetric network, the input wave is divided equally between the two output ports via coupling.(13) The major challenge in designing conventional (quarter wavelength) branch line couplers are their bulky size and its typically narrow bandwidths of 10% to 20%....
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18 Oct 2010
TL;DR: A fully-integrated 16-element 60-GHz phased-array receiver is implemented in IBM 0.12-μm SiGe BiCMOS technology and a detailed analysis of the noise trade-offs in the receiver array design is presented to motivate architectural choices.
Abstract: A phased-array transmitter (TX) for multi-Gb/s non-line-of-sight links in the four frequency channels of the IEEE 802.15.3c standard (58.32 to 64.8 GHz) is fully integrated in a 0.12-μm SiGe BiCMOS process. It consists of an up-conversion core followed by a 1:16 power distribution tree, 16 phase-shifting front-ends, and a digital control unit. The TX core is a two-step sliding-IF up-conversion chain with frequency synthesizer that features 40 dB of gain programmability, I/Q balance and LO leakage correction, and a modulator for 802.15.3c common-mode signaling. The tradeoffs involved in the implementation of a 1:16 power distribution network are analyzed and a hybrid passive/active distribution tree architecture is introduced. Each of the 16 front-ends consists of a balanced passive phase shifter and a variable-gain, 3-stage PA that features oP1dB programmability through the bias control of the its final stage. All of the chip features are digitally controllable and individual memory arrays are integrated at each front-end to enable fast beam steering through a high-speed parallel interface. The IC occupies 44 mm and is fully characterized on wafer. The TX delivers 9 to 13.5 dBm oPidB per element at 60.48 GHz with a total power consumption of 3.8 to 6.2 W. Each element attains a phase-shift range >360° with an amplitude variation <;±1 dB across phase settings and adjacent elements. Measurement results from a packaged IC in an antenna chamber are also presented including the demonstration of spatial power combining up to +40 dBm EIRP and 16-element radiation patterns.
445 citations
TL;DR: In this article, a method of miniaturizing branch-line 90 degrees hybrid and 180 degrees rat-race hybrid was proposed, which utilizes combinations of short high-impedance transmission lines and shunt lumped capacitors.
Abstract: A method of miniaturizing branch-line 90 degrees hybrids and 180 degrees rat-race hybrids is proposed The method utilizes combinations of short high-impedance transmission lines and shunt lumped capacitors The hybrids were fabricated on GaAs substrates and the validity and effectiveness of the method were confirmed through experiments at 25 GHz and 11 GHz The fabricated hybrids demonstrate excellent design accuracy at high frequencies, with a circuit size that is more than 80% smaller than that of conventional hybrids These hybrids are particularly suitable for uniplanar MMICs where necessary shunt connections are easily made >
426 citations
"A review of hybrid couplers: State-..." refers background in this paper
...Although the area of the circle can be reduced by using lumped elements to reduce the length of the transmission line, the inductance is usually low.(49,50) In the conventional rat-race hybrid coupler presented in Reference 51, the ring structure adopted to power split resulted in a bandwidth of about 18%, as shown in Figure 6....
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