CiteULike: dcastro's branch-line

Analysis and Design of Branch-Line Hybrids with Coupled Lines

VK Tripathi — 2008-04-16T19:41:10-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 32, No. 4. (1984), pp. 427-432.

The scattering parameters of four-ports consisting of coupled lines with coupled or uncoupled connecting branches are derived in terms of the even- and odd-mode impedances and the lengths of the lines. These are used to analyze and formulate basic design procedures for the application of these structures as directional couplers including 0° and 90° 3-dB hybrids. The proposed new structures are quite compact at lower frequencies as compared to conventional uncoupled branch-line and rat-race hybrids. The results for the case of the coupled-line four-port with uncoupled branch lines also lead to closed-form expressions for the lengths and impedances of the lines required to nullify the effect of coupling between the main lines of a conventional branch-line coupler for use at higher frequencies. The measured response of the fabricated couplers is in good agreement with the theoretical predictions.

Compact wide-band branch-line hybrids

Young-Hoon Chun — 2007-12-06T16:59:33-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 54, No. 2. (2006), pp. 704-709.

Wide-band branch-line couplers are designed and tested. The proposed couplers feature compact size on a single circuit layer structure without via-holes. For the broad-band property and cost effectiveness, we have designed a four-branch hybrid with mixed distributed and lumped distributed elements. Analysis on the equivalent circuits was performed carefully in order to obtain a sufficient bandwidth with reduced design area. The fabricated hybrids have the fractional bandwidth larger than 56% at the center frequency of 2 GHz. They also show size reduction up to 55.2% compared with the conventional design method.

Synthesizing Microstrip Branch-Line Couplers With Predetermined Compact Size and Bandwidth

CW Tang — 2007-12-06T16:52:53-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 55, No. 9. (2007), pp. 1926-1934.

<para> A new method for designing the microstrip branch-line couplers with predetermined compact size and bandwidth is proposed in this paper. With the proposed approach, the size of the quarter-wavelength transmission line in the branch-line coupler can be reduced greatly. In addition, the proposed couplers can be easily fabricated on the printed circuit board without any lumped element. A chart concludes the relationship between bandwidth and size reduction rate. It shows that open stubs with low impedance perform better than those with high impedance; moreover, the more open stubs with low impedance utilized, the broader the bandwidth will be. Furthermore, the measured frequency responses show good agreement with the theoretical results. </para>

A compact branch-line coupler using discontinuous microstrip lines

Kae-Oh Sun — 2007-12-06T16:52:26-00:00

Microwave and Wireless Components Letters, IEEE, Vol. 15, No. 8. (2005), pp. 519-520.

We introduce a branch-line coupler using discontinuous microstrip lines whose size is significantly reduced relative to the standard design. We manipulate the reactive characteristics of discontinuities in its microstrip lines to achieve a physical size reduction of almost 60% with comparable performance.

A Method of Analysis of Symmetrical Four-Port Networks

J Reed — 2007-11-20T10:55:18-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 4, No. 4. (1956), pp. 246-252.

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.

Miniaturized fractal rat-race, branch-line, and coupled-line hybrids

H Ghali — 2007-11-20T10:54:12-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 52, No. 11. (2004), pp. 2513-2520.

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.

New Type of Branch-Line Hybrios

H Ashoka — 2007-11-20T08:42:13-00:00

European Microwave Conference, 1988. 18th (1988), pp. 785-790.

New type of branch-line hybrids which provide the designer with a great degree of freedom in the choice of line impedances is presented. The hybrids can also be experimentally tuned to correct any imbalance in the outputs or to shift the frequency of operation, thus reducing the development effort.

Miniaturization and harmonic suppression of branch-line and rat-race hybrid coupler using compensated spiral compact microstrip resonant cell

Jianzhong Gu — 2007-11-20T08:41:41-00:00

Microwave Symposium Digest, 2005 IEEE MTT-S International (2005), pp. 1211-1214.

In this paper, a compensated spiral compact microstrip resonant cell (SCMRC) is applied to design a miniaturized microstrip rat-race and branch-line hybrid coupler. The proposed structures can achieve both a significant reduction of size and harmonic suppression. As the SCMRC are constructed entirely from microstrip lines, the couplers are easily fabricated using conventional printed-circuit board fabrication process. The proposed rat-race coupler occupies only 30% of conventional one's area, while the area of the branch-line coupler with the compensated SCMRC is 24% of the conventional case. On the other hand, the performance of the proposed couplers is as good as that of the corresponding conventional structures and deep harmonic suppression in addition. The design and simulation have been performed using full-wave analysis based on ADS Momentum

A novel planar branch-line coupler design for dual-band applications

Fai-Leung Wong — 2007-11-20T08:41:16-00:00

Microwave Symposium Digest, 2004 IEEE MTT-S International, Vol. 2 (2004), pp. 903-906 Vol.2.

This paper presents, for the first time, the design of a branch-line coupler that can operate at two arbitrary frequency bands. Moreover, design equations of the coupler with sub-optimum performance is analytically derived. The proposed circuit also features compact size, planar structure and low-loss. For verification, both simulated and measured results of a microstrip branch-line coupler operating at 900/1500 MHz are shown.

A novel approach to the design and implementation of dual-band compact planar 90/spl deg/ branch-line coupler

KKM Cheng — 2007-11-20T08:40:48-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 52, No. 11. (2004), pp. 2458-2463.

This paper presents the design of a novel branch-line coupler that can operate at two arbitrary frequencies. The proposed circuit also features compact size and planar structure. Explicit design formulas of the proposed dual-band coupler are analytically derived. Moreover, practical issues such as the realization of branch-line impedance and optimum choice of circuit topologies are addressed. For verification purposes, both simulated and measured results of a microstrip branch-line coupler operating at 900/2000 MHz are included.

Phase-agile branch-line couplers using metamaterial lines

R Islam — 2007-11-20T08:40:26-00:00

Microwave and Wireless Components Letters, IEEE, Vol. 14, No. 7. (2004), pp. 340-342.

Two branch-line couplers are introduced that utilize a combination of regular microstrip (MS) and negative-refractive-index (NRI) lines. Interesting phase compensation (0/spl deg/ phase shift) at the output port and a choice of /spl plusmn/90/spl deg/ phase shift at the through port, with respect to the input, are possible. On the other hand, one of the dimensions of the coupler is significantly reduced, compared to a corresponding conventional branch-line coupler, but without any bandwidth degradation.

Optimum Design of 3-Db Branch-Line Couplers Using Microstrip Lines

2007-11-20T08:40:00-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 83, No. 8. (1983), pp. 674-678.

A computer-aided design is described that makes it possible to reduce the internal impedance levels of branch-line couplers so that they may be physically constructed by microstrip lines, where the Fletcher-Powell search method has been used to optimize the design. Because microstrip lines are severely restricted in their usable impedance range, the 3-dB couplers presented here should be useful for numerous balanced-type components such as balanced mixers. The validity of the design has been experimentally verified in the microwave and millimeter-wave region.

Compact planar microstripline branch-line and rat-race couplers

KW Eccleston — 2007-11-20T08:39:30-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 51, No. 10. (2003), pp. 2119-2125.

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/spl deg/ or 270/spl deg/, 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.

Broad-band uniplanar hybrid-ring and branch-line couplers

Chien-Hsun Ho — 2007-11-20T08:38:55-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 41, No. 12. (1993), pp. 2116-2125.

Novel uniplanar 180° and 190° hybrids suitable for MIC and MMIC applications are described. The uniplanar crossover hybrid-ring coupler using a coplanar waveguide (CPW) and slotline provides substantially improved amplitude and phase characteristics over a broad bandwidth compared to conventional microstrip hybrid-ring couplers. Experimental results show that the new coupler has a bandwidth of more than one octave from 2 GHz to 4 GHz with a ±0.4-dB power dividing balance and a ±1° phase balance. A uniplanar two-branch directional coupler using a coupled rectangular slotline ring has also been developed. CPW-to-slotline transitions using uniform and nonuniform CPWs or slotlines are also discussed. These transitions are uniplanar and simple to fabricate. No via-holes are needed for ground connections, and integration with solid-state devices is easy. A pair of broadband transitions using CPW shorts and slotline radial stubs is demonstrated with a 1-dB bandwidth of more than 5.2:1

Hybrid Branchline Couplers -- A Useful New Class of Directional Couplers

B Schiek — 2007-11-20T08:38:15-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 22, No. 10. (1974), pp. 864-869.

The hybrid branchline coupler consists of two transmission lines connected alternately by /spl lambda//4 shunt and series branches. The analysis of this structure leads to a class of directional couplers of which the parallel transmission-line and the de Ronde strip-slot types may be regarded as special cases. From the precise design data thus available, a number of 3-dB strip-slot couplers have been built in C band and X band with a performance close to the predicted one.

Branchline-couplers with improved design flexibility and broad bandwidth

B Mayer — 2007-11-20T08:37:39-00:00

Microwave Symposium Digest, 1990., IEEE MTT-S International (1990), pp. 391-394 vol.1.

Analytical formulas that make it possible to fully exploit the design flexibility inherent in two-arm branchline-couplers with open stubs at the symmetry-planes in order to avoid low-impedance lines are derived. A broadbanding procedure that improves the operating bandwidth of a two-arm coupler up to 40% while maintaining very flat coupling characteristics is given. To verify the theoretical work, various 3-dB couplers were built. Two examples are given for two-arm couplers: (1) a hybrid coupler with two series λ/2-length branches in cascade and (2) a hybrid coupler with one series λ/2-length branch and one λ/2-length open stub in parallel

New broadband branchline coupler

B Mayer — 2007-11-20T08:37:11-00:00

Electronics Letters, Vol. 26, No. 18. (1990), pp. 1477-1478.

A broadband 3 dB/90° branchline coupler in microstrip techniques is presented. The circuit shows input matching and isolation better than -29 dB, a power imbalance of less than 0.1 dB and a maximum phase deviation of ±0.1° from the ideal value of 90° over a bandwidth of 38%

A branch-line coupler with two arbitrary operating frequencies using left-handed transmission lines

I-Hsiang Lin — 2007-11-07T18:35:54-00:00

Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 1 (2003), pp. 325-328 vol.1.

A branch-line coupler (BLC) working at two arbitrary frequencies using left-handed (LH) transmission lines (TLs) is presented. The analysis of the structure is based on the even-odd mode analysis of the conventional BLC as well as a recently developed model for the LH-TL. We demonstrate that the two operating frequencies can be obtained by tuning the phase slope of the different line sections. A prototype is demonstrated by both simulation and measurement results. The operating frequencies of the two pass-bands are 920 MHz and 1740 MHz, respectively.