1

微波電路期中 /期末報告 論文研討 : Y.S. Lin , C. H. Chen, “Novel Lumped-Element Uniplanar

Transitions”, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 49, NO. 12, DECEMBER 2001

報告人 : 碩研光電一甲 MA0L0201 陳建翔

Southern Taiwan UniversitySouthern Taiwan University Department of Electronic Engineering

2

Abstract

In this study, various compact lumped-element coplanar waveguide (CPW)-to-slotline and finite-ground coplanar waveguide (FGCPW)-to-coplanar stripline (CPS) transition structures are developed and carefully examined. Specifically, the performance of proposed basic lumped-element transitions can easily be adjusted through the control of and values, while the design of lumped element Marchand-balun-type transitions may be accomplished by the use of conventional filter synthesis techniques.

3

Coplanar waveguide (CPW)-to-slotline

Substrate(FR4)

εr 4.3

tanδ 0.022

h 1.6mm

CPW

Strip width 0.75mm

Slot width 1mm

Slotline

Slot width 1mm

Finger capacitor

Finger width 0.5mm

Finger length 3.4mm

Gap width 0.2mm

LC Total area

(λ/28) (λ/12)‧

‧CPW-to-slotline layout

4

Coplanar waveguide (CPW)-to-slotline

‧CPW-to-slotline equivalent-circuit model

This model is based on three assumptions: First, ‧the CPW and slotline sections are modeled as transmission lines despitethe non-TEM nature of slotline. ‧Second, the detailed discontinuity effect of the CPW–slotline T-junction is neglected.‧Third, the interactions between the lumped-element circuit and the transmission lines are not taken into account.

5

Measured and simulated results

‧Measured:HP8510 networkanalyzer with thru-reflect-line (TRL) calibration‧Simulated : based on theequivalent-circuit model

Measured

1.5-dB passband 1.96~3.3GHz

Simulated

Inductance 5.5nH

Capacitance 0.6525pF

Center frequency 2.66GHz

6

“Ring-type L” CPW-to-slotline transition

Finger capacitor

Finger width 0.5mm

Finger length 3.2mm

Gap width 0.2mm

Ring-type L

Rr 2.5mm

gapr 0.5mm

Total area

(λ/30) (λ/30)‧

7

Measured and simulated results

Measured

1.5-dB passband 1.53~2.76GHz

Simulated

Inductance 5.89nH

Capacitance 0.6525pF

Center frequency 2.57GHz

8

Finite-ground coplanar waveguide (FGCPW)-to-coplanar stripline (CPS)

FGCPW

Strip width 0.45mm

Slot width 0.6mm

Finite ground-plane 4mm

CPS

Strip width 4mm

Slot width 0.6mm

Finger capacitor

Finger width 0.5mm

Finger length 3.7mm

Gap width 0.3mm

Shorter metal strip

Strip width 0.5mm

Strip length 12.05mm

Total area

(λ/28) (λ/14)‧

9

Measured and simulated results

Measured

1.5-dB passband 1.17~3.41GHz

Simulated

Inductance 10.35nH

Capacitance 0.597pF

Center frequency 2.02GHz

10

Metal-insulator-metal (MIM) configuration

Shorter metal strip

Strip width 0.5mm

Strip length 5mm

Metal-insulator ( Duroid )-metal

Area 2.4mm×3mm

εr 10.2

tanδ 0.002

h 0.635mm

11

Measured and simulated results

Measured

1.5-dB passband 1.69~3.1GHz

Simulated

Inductance 3.53nH

Capacitance 1pF

Center frequency 2.67GHz

12

Finite-ground coplanar waveguide (FGCPW)-to-coplanar stripline (CPS)

13

Measured and simulated results

14

Measured power losses

15

Marchand-balun-type

‧The conventional Marchand-balun-type structure and S21 (dB)

16

Marchand-balun-type

Ls

Strip width 0.4mm

Strip length 5.5mm

Cs

Finger width 0.4mm

Finger length 2.9mm

Gap width 0.2mm

Lp

Rr 2.1mm

Gap width 1mm

Cp

Finger width 0.5mm

Finger length 2.2mm

Gap width 0.3mm

LC Total area

(λ/7) (λ/10)and(λ/8) (λ/12)‧ ‧

17

Measured and simulated results

Measured

1.5-dB passband

1.12~4.38GHz

Simulated

Ls 3.75nH

Cs 0.75pF

Lp 7.5nH

Cp 0.375pF

Center frequency

3GHz

18

Marchand-balun-type

19

Measured and simulated results

20

Conclusion

For the basic lumped-element uniplanar transitions, the center frequency and bandwidth can easily be determined and controlled by an adjustment of and values.

For design and modeling purpose, effective and simple equivalent-circuit models have also been established. The proposed lumped-element transitions have the merits of very compact size, low power losses, moderate bandwidth, and easy characterization, thus providing simple and effective interconnections between CPW and slotline/CPS.

心得與感想

使用 CPW、 slotline、 FGCPW 、 CPS這些集總元件來實現傳統的 open short 電路，不只能縮小其面積也能藉由調整集總元件，來控制電路的等效 LC ，藉此來達到我們所想要的頻率以及頻寬。而這樣的方法，對於現在設計小型薄型化的通訊設備有相當大的幫助。

21

22

References

[1] K. C. Gupta, R. Garg, I. Bahl, and P. Bhartia, Microstrip Lines and Slotlines, 2nd ed. Norwoodl, MA: Artech House, 1996, ch. 5 and 7.

[2] M. Riaziat, R. Majidi-Ahy, and I.-J. Feng, “Propagation modes anddispersion characteristics of coplanar waveguides,” IEEE Trans.Microwave Theory Tech., vol. 38, pp. 245–251, Mar. 1990.

[3] L. Fan and K. Chang, “Uniplanar power dividers using coupled CPW and asymmetrical CPS for MIC’s and MMIC’s,” IEEE Trans.Microwave Theory Tech., vol. 44, pp. 2411–2419, Dec. 1996.

[4] F. L. Lin, C. W. Chiu, and R. B. Wu, “Coplanar waveguide bandpass filter—A ribbon of brick wall design,” IEEE Trans. Microwave Theory Tech., vol. 43, pp. 1589–1596, July 1995.

[5] L. Fan, B. Heimer, and K. Chang, “Uniplanar hybrid couplers using asymmetrical coplanar strip lines,” in IEEE MTT-S Int. Microwave Symp. Dig., 1997, pp. 273–276.

[6] D. Cahana, “A new coplanar waveguide/slotline double-balanced mixer,” in IEEE MTT-S Int. Microwave Symp. Dig., 1989, pp. 967–968.

[7] Y.-D. Lin and S.-N. Tsai, “Coplanar waveguide-fed uniplanar bow-tie antenna,” IEEE Trans. Antennas Propagat., vol. 45, pp. 305–306, Feb. 1997.

[8] C.-H. Ho, L. Fan, and K. Chang, “Experimental investigations of CPWslotline transitions for uniplanar microwave integrated circuits,” in IEEE MTT-S Int. Microwave Symp. Dig., 1993, pp. 877–880.

[9] K. Hettak, N. Dib, A. Sheta, A. A. Omar, G.-Y. Delisle, M. Stubbs, and S. Toutain, “New miniature broad-band CPW-to-slotline transitions,” IEEE Trans. Microwave Theory Tech., vol. 48, pp. 138–146, Jan. 2000.

[10] V. Trifunovic´ and B. Jokanovic´, “Review of printed Marchand and double Y baluns: Characteristics and application,” IEEE Trans. Microwave Theory Tech., vol. 42, pp. 1454–1462, Aug. 1994.

23

References

[11] K.-P. Ma and T. Itoh, “A new broadband coplanar waveguide to slotline transition,” in IEEE MTT-S Int. Microwave Symp. Dig., 1997, pp. 1627–1630.

[12] Y.-S. Lin and C. H. Chen, “Design and modeling of twin-spiral coplanar waveguide-to-slotline transitions,” IEEE Trans. Microwave Theory Tech., vol. 48, pp. 463–466, Mar. 2000.

[13] L. Zhu and K. Wu, “Hybrid FGCPW/CPS scheme in the building block design of low-cost uniplanar and multilayer circuit and antenna,” in IEEE MTT-S Int. Microwave Symp. Dig., 1999, pp. 867–870.

[14] S.-G. Mao, C.-T. Hwang, R.-B. Wu, and C. H. Chen, “Analysis of coplanar waveguide-to-coplanar stripline transitions,” IEEE Trans. Microwave Theory Tech., vol. 48, pp. 23–29, Jan. 2000.

[15] Y.-S. Lin and C. H. Chen, “Novel lumped-element coplanar waveguide- to-slotline transitions,” in IEEE MTT-S Int. Microwave Symp. Dig., 1999, pp. 1427–1430.

[16] S. S. Gevorgian, T. Martinsson, L. J. P. Linner, and E. L.Kollberg, “CAD models for multilayered substrate interdigital capacitors,” IEEE Trans. Microwave Theory Tech., vol. 44, pp. 896–904, June 1996.

[17] M. Ribo, J. de la Cruz, and L. Pradell, “Circuit model for slotline-tocoplanar waveguide asymmetrical transitions,” Electron. Lett., vol. 35, pp. 1153–1155, July 8, 1999.

[18] A. E. Ruehli, “Inductance calculations in a complex integrated circuit environment,” IBM J. Res. Develop., vol. 16, pp. 470–481, Sept. 1972.

[19] M. Ribo and L. Pradell, “Circuit model for a coplanar-slotline cross,” IEEE Microwave Guided Wave Lett., vol. 10, pp. 511–513, Dec. 2000.

[20] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures. Norwood, MA: Artech House, 1980.