Design of an Economical Compact Coaxial Cavity Combline Filter for 3G TD Base Station

Abstract:

The cross coupled microwave filter is widely used in the communication sub system .The synthesis of the cross coupled filter is from prescribed transmission zeros and return loss till the attainment of the coupling matrix of each cavity. A compact narrowband combline high rejection filter with cross coupled is presented. A configureiton using identical resonator post with capacitance-loading is introduced. Tested results show that with order-8 filter center frequency at 2017.5MHz, return loss lower than-25dB can be achieved over a relative bandwidth of 1.29%. A sample filter has been fabricated and tested result confirmed the theory result.

• Periodical: Applied Mechanics and Materials (Volume 704)
• Pages: 219-224
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.704.219
• Online since: December 2014
• Authors: Guang Ming Zheng
• Keywords: Combline Filter, Coupling Coefficient, Coupling Matrix Synthesis, CST

References

[1] Atia A E, Wiliams A E, Newcomb R W. Narrow-band Multiple-coupledC avitiesS ynthesis[J]. IEEE Trans. Circuit and Systems, 19 74, 2 1( 5): 64 9-655.

[2] Cameron R J, Rhodes J D. Asymmetric Realization of Dual-mode Bandpass Fiter[J]. I EEE Trans. M icrowave Theory Tech, 19 81, 29 ( 1): 64 9- 655.

[3] BellH C . C anonicalA symmetricC oupled-resonatorF ilters[J]. IEE ET rans. M icrowaveT heroyT ech, 1 982, 3 0(1): 1335-1340.

[4] M. Hoft., Bottom Coupling of Combline Resonators for Hybrid Dielectric/Air-Cavity Bandpass Filters, European Microwave Conference., pp.1323-1326, Sept. (2006).

DOI: 10.1109/eumc.2006.281259

[5] M. E. Van Valkenburg, Introduction to Modern Network Synthesis. New York: Wiley, (1960).

[6] Cameron R J. General Coupling Matrix Synthesis Methods for C heybeshevf ilteringf unction[J]. IE EET rans. M icrowave Th eory andT ech., 1999, 47 ( 4): 433 -442.

[7] R. J. Cameron, Advanced coupling matrix synthesis techniques for microwave filters, IEEE Trans. Microw. Theory Tech., vol. 51, no. 1, p.1–10, Jan. (2003).

DOI: 10.1109/tmtt.2002.806937

[8] Amari S, Rosenberg U. Adaptive Synthesis and Design of Re sonatorF iltersw ithS ource/load-multiresonator C- oupling [J] . I EEE Trans. M icrowaveT heory Tech., 2002, 5 0 (8): 1969-(1978).

[9] Amari S, Rosenberg U. Direct Synthesis of a New Class of Ba ndstopF iters[J]. IE EE Trans. M icrowaveT heory Tech, 2004, 52(5): 607-616.

[10] Lee J. Coupling Matrix of Worder Dual-modeA symmetric CanonicalF ilter[J]. IE EE Microwave and OpticalT echnolog yL et., 2003, 38 ( 7): 64 ~67.

[11] Stefano Tamiazzo and Giuseppe Macchiarella, An Analytical Technique for the Synthesis of Cascaded N-Tuplets Cross Coupled Resonators Microwave Filters Using Matrix Rotations, IEEE Trans. Microw. Theory Tech., vol 53, no 5, pp.1693-1698 MAY (2005).

DOI: 10.1109/tmtt.2005.847065