Broadband lumped-element 180-degree hybrids utilizing lattice circuits

Kawai, Tadashi; Kokubo, Yasuaki; Ohta, Isao

doi:10.1109/mwsym.2001.966836

Cited by 16 publications

(11 citation statements)

References 5 publications

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“…Furthermore, if the phase reference of one port is fixed, for instance, the phase of equals zero, then (4) where is the phase of and [9]. In a dual-band operation, (2) and (3) has to hold at two different and uncorrelated frequencies. The conventional BL hybrid acts as a hybrid at those frequencies and , at which the BL lengths are and , respectively, with being the effective wavelength at (see Fig.…”

Section: A Descriptionmentioning

confidence: 99%

“…This electrical length is the one at the central frequency of the filter-shaped response so all the other transmission-line lengths are already fixed if we choose . Now we have to impose (2) and (3) only at the frequency since is placed symmetrical to with respect to . The set of (A-1)-(A-4) can be solved numerically to find the optimum values of , , and for a given normalized frequency (see Fig.…”

Section: B Analysis and Designmentioning

confidence: 99%

“…5). Note that condition (3) is practically achieved at 5.8 GHz since and approximately cross at this frequency, but unfortunately, the isolation and return loss are not good enough [see condition (2)]. …”

Section: Hybrid For Wlan Systemsmentioning

confidence: 99%

“…There are two generic approaches to achieve functionality at two frequencies and , which are away, either designing a broad-band hybrid whose bandwidth is greater than , or designing a dual-band hybrid whose relative bandwidths ( and ) at each frequency are large enough for the frequency bands assigned to the service. Broad-band hybrids can be designed either using quasi-lumped elements, usually implemented with monolithic-microwave integrated-circuit (MMIC) technology [2], [3] or enhancing the bandwidth of distributed planar elements by cascading several of them [4]. Dual-band hybrids can also be designed using several approaches.…”

Section: Introductionmentioning

confidence: 99%

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Dual-band planar quadrature hybrid with enhanced bandwidth response

Collado

Grau

Flaviis

2006

IEEE Trans. Microwave Theory Techn.

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Abstract-This paper presents the theory, design procedure, and implementation of a dual-band planar quadrature hybrid with enhanced bandwidth. The topology of the circuit is a three-branch-line (3-BL) quadrature hybrid, which provides much larger flexibility to allocate the desired operating frequencies and necessary bandwidths than other previously published configurations. A performance comparison with other dual-band planar topologies is presented. Finally, a 3-BL quadrature hybrid for dual band (2.4 and 5 GHz) wireless local area network systems was fabricated, aimed to cover the bands corresponding to the standards IEEE802.11a/b. The measurements show a 16% and 18% bandwidth for the lower and upper frequency, respectively, satisfying and exceeding the bandwidth requirements for the above standards.Index Terms-Dual-band hybrid, planar quadrature hybrid, wireless local area network (WLAN) systems.

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Section: A Descriptionmentioning

confidence: 99%

Section: B Analysis and Designmentioning

confidence: 99%

Section: Hybrid For Wlan Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dual-band planar quadrature hybrid with enhanced bandwidth response

Collado

Grau

Flaviis

2006

IEEE Trans. Microwave Theory Techn.

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“…Lumped elements may be introduced at strategic points [9], [11]- [13] or the coupler completely realized with lumped elements [14]- [17], thereby resulting in significant size reduction; but are more suited to MMIC realization. Certain photonic-bandgap (PBG) structures [18] can be used to shorten the microstriplines [19] to result in miniaturization without additional components.…”

mentioning

confidence: 99%

Compact planar microstripline branch-line and rat-race couplers

Eccleston

Ong

2003

IEEE Trans. Microwave Theory Techn.

375

204

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Abstract-Both branch-line and rat-race couplers are easily realized using planar circuit technology as they employ only transmission lines without additional components. However, as the electrical lengths of the transmission line elements are either 90 or 270 , such couplers consume a significant amount of circuit area. This paper shows the development of branch-line and rat-race couplers that use artificial transmission lines (ATLs) in place of conventional transmission lines resulting in significant size reduction. As the ATLs are constructed entirely from microstriplines, the couplers are easily fabricated using conventional printed-circuit processes. The design formulas developed for the ATLs are explicit. Full-wave simulation and experimental results were used to confirm the design approach for hybrids operating at 1.8 GHz. The frequency response of the proposed hybrids is similar to conventional hybrids.

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Shortened directional coupler using slow wave structure of periodically loaded capacitance and inductance

Zhong

Sun³

et al. 2015

Int J Numerical Modelling

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This paper proposes an analytically based approach for the design of a length-reduced directional coupler. This method of reduction is realizing the directional coupler's impedance transformers by using slow wave structures. These slow wave structures are designed by transmission lines periodically loading both shunt capacitances and series inductances. Loaded capacitance is realized by stub shunt capacitance on the top layer; at the same time, loaded inductance is realized by electromagnetic band gap structure on ground. Increasing parallel capacitance and series inductance can reduce the phase velocity of the propagating waves and hence engender higher electric lengths using smaller physical lengths. A directional coupler is designed using this slow wave structure, and the performance of coupling is analyzed with the generalized coupled-mode theory. The design methodology is validated with the design of a length-reduced directional coupler at 0.7 GHz. An approximate length reduction of 54% is achieved with this technique compared with the conventional directional coupler. The electromagnetic simulation and experimental results validate the proposed approach. Table I. Physical parameters of the coupler.Coupler's dimension (mm) W M1 = 2.3, W M2 = 1.4, W SLOT = 0.4, W STUB = 0.4, W M3 = 0.6, W M4 = 1, L M = 5, L S = 12, L = 31, S = 0.12, 490 C. ZHONG ET AL.

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Broadband lumped-element 180-degree hybrids utilizing lattice circuits

Cited by 16 publications

References 5 publications

Dual-band planar quadrature hybrid with enhanced bandwidth response

Dual-band planar quadrature hybrid with enhanced bandwidth response

Compact planar microstripline branch-line and rat-race couplers

Shortened directional coupler using slow wave structure of periodically loaded capacitance and inductance

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