Abstract.
At present passive microstrip devices have found wide application in the modern
radio engineering. Directional couplers can be used in communication, antennas,
radio measurements. Also they can be implemented in the power splitters,
modulators, adders, shifters. Standard design branch-line coupler consists of
four quarter-wave sections of transmission line. It should be noted that the
dimensions of the device depend on the frequency. The higher it is, the greater
the area of the device. Therefore it is necessary to use different approaches to
reduce the size of such devices, maintaining their original characteristics in a
wide band of frequencies. In order to eliminate the spurious bandwidth, to
reduce the size and efficiency of production, structures which function as
quarter-wave segments are used. Such structures are much shorter in length, and
they can be made by standard techniques: the etching of printed circuit boards.
Microstrip capacitances, which are the part of the proposed structures, are
placed inside the free space of the device. To account for the influence of
adjacent conductive lines to each other and other factors we use the AWR DE 13.
The compact design has an area of 554 mm2, which is 78% less than conventional
construction. The simulation results were made as prototype of a compact clutch.
Measurement of parameters was carried out using a vector network analyzer Rohde
& Schwarz ZVA 24 and calibration kit K52. As a result we obtained compact
design, easy to manufacture, which may find various applications in microwave
technology. Further reduction of the area of the coupler is possible by
optimizing the structures and their location. However, the increasing of
the degree of miniaturization leads to the decrease in bandwidth.
Key words: microstrip line, miniaturization, branch-line coupler.
References
1. Kimberley W.
Eccleston, and Sebastian H.M. Ong, “Compact Planar Microstripline Branch-Line
and Rat-Race Couplers,” IEEE Trans. Microw. Theory Tech.,
2003,
Vol. 51, No. 10, pp.
2119-2125.
2. Kai-Yu Tsai,
Hao-Shun Yang, Jau-Horng Chen, and Yi-Jan Emery Chen, “A miniaturized 2 dB
Branch-Line Hybrid Coupler With Harmonics Suppression,” IEEE Microw. Wireless
Compon.Lett.,
2011,
Vol. 21, No. 10, pp. 537-539.
3. C. W. Tang and
M.-G.Chen, "Synthesizing microstrip branch-line coupler with predetermined
compact size and bandwidth," IEEE Trans. Microw. Theory Tech.,
2007,
Vol. 55,
No. 9, pp. 1926-1934.
4. Chao-Wei Wang,
Tzyh-Ghuang Ma and Chang-Fa Yang, “A new planar artificial transmission line
and its applications to a miniaturized butler matrix,” IEEE Trans. Microw.
Theory Tech., 2007, Vol. 55, No. 12, pp. 2792-2801.
5. Kimberley W.
Eccleston and Sebastian H. M., “Compact planar microstripline branch-line and
rat-race couplers,” IEEE Trans. Microw. Theory Tech., 2003, Vol. 51, No. 10, pp.
2119-2125.
6. S.-S. Liao and
J.-T. Peng, "Compact planar microstrip branch-line couplers using the
quasi-lumped elements approach with nonsymmetrical and symmetrical T-shaped
structure," IEEE Trans. Microw. TheoryTech., 2006, Vol. 54, No. 9, pp. 3508-3514.
7. N. N.
Shchetinin, V. A. Melnik, "Compact microstrip 3 dB quadrature directional
coupler". Vestnik Voronezhskogo Instituta FSIN ROSSII - Proceedings of Voronezh institute of
FSIN RF. 2014, No. 4, pp. 26-28. (in Russian).
8. N. N.
Shchetinin, A. V. Ostankov, E. I. Vorobjeva, "Mathematical model for the
microstrip directional coupler on a quasi-lumped element," Vestnik
Voronrzhskogo Gosudarstvennogo Tekhnicheskogo Universiteta. - Proceedings of
Voronezh State Technical University. 2014, Vol. 10, No. 3-1, pp. 66-70 (in
Russian).
9. Chao-Hsiung
Tseng and Chih-Lin Chang, “A rigorous design methodology for compact planar
branch-line and rat-race couplers with asymmetrical T-structure,” IEEE Trans. Microw. Theory Tech.,
2012, Vol. 60, No. 7, pp. 2085-2092.
10. K. W. Eccleston and S. H. M. Ong, "Compact planar
microstripline branch-line and rat-race coupler," IEEE Trans. Microw.
Theory Tech., 2003, Vol. 51, No. 10, pp. 2119-2125.
11. Wei-Shin Chang and Chi-Yang Chang, “A high slow-wave factor
microstrip structure with simple design formulas and its application to
microwave circuit design,” IEEE Trans. Microw. Theory Tech., 2002, Vol. 60,
No. 11,
pp. 3376-3383.
12.
Hani Ghali and Tarek A. Moselhy “Miniaturized fractal rat-race,
branch-line, and coupled-line hybrids,” IEEE Trans. Microw. Theory Tech.,
2004, Vol.
52, No. 11, pp. 2513-2520.