диафрагмированные волноводные фильтры / 59b1b1be-bd43-460e-aec8-f12a78768fa9

Abstract— This paper presents electromagnetic simulation of a dielectric-filled rectangular waveguide bandpass filter structure for modern wireless system applications. Two bandpass filters have been designed and simulated at centre frequencies of 11.85 and 14.25 GHz, respectively. A significant size reduction is achieved.

Keywords-waveguide filters; electromagnetic simulation;

I.INTRODUCTION

Over the past few decades rectangular waveguide filters have been a sustainable solution for low-cost, low-loss and high power filters for modern microwave and millimeter-wave applications. However, despite their favorable performances, the attenuation in the second stopband may often be too low for diplexers and multiplexers [1]-[3]. In order to improve the performances of rectangular waveguide bandpass filters a number of approaches have been proposed [4]. By employing ridged resonators, we can change the cutoff frequency of a standard rectangular waveguide resonator and achieve shorter resonator length.

This paper proposes replacement of standard section of rectangular waveguide E-plane filters with the dielectric-filled resonator loaded structures. These structures, while improving compactness, maintain the low-cost and mass-producible characteristics of conventional metal insert E-plane technology.

II.PROPOSED DIELECTRIC-FILLED WAVEGUIDE FILTERS

The proposed dielectric-filled rectangular waveguide bandpass filter structure is shown in Fig. 1. The proposed filter structure is composed on two parts: a rectangular waveguide filled with dielectric material which has relative dielectric permittivity of 4.00 and printed slab-circuit. The substrate is Rogers RO4003 with a thickness of 0.508 mm, dielectric constant of 3.55 and the metallization thickness of 0.017 mm. The slab is inserted in the line of symmetry of hollow dielectric-filled rectangular waveguide of width a and height b. Rectangular waveguides of widths a = 10.00/7.899 mm, and heights b = 2.25 mm have been used as housings to fit these filter structures.

Filter I

Filter II

Figure 1. Configurations of dielectric-filled waveguide bandpass filters.

(b)

Figure 2. Simulated Insertion and Return losses of the proposed bandpass filters (a) Filter I (b) Filter II.

Filter II. Construct a dielectric-filled rectangular waveguide bandapss filter to provide a passband return loss >15 dB from 10.95 to 12.75 GHz with attenuation > 35 dB at 14 GHz.

Dimensions of the proposed filters at 11.85 and 14.25 GHz respectively are given in Table I. The proposed filters, Filter 1 and Filter 2, have their total structure lengths of 30 mm and 62.71 mm respectively. Simulated insertion and return losses of the proposed filters I and II are shown in Fig. 2.

III.CONCLUSION

A new class of dielectric-filled rectangular waveguide bandpass filter structures, has been presented. The proposed structures can be easily realized with metallo-dielectric inserts within the standard dielectric-filled rectangular waveguides. These filter structures have been designed and simulated at centre frequency 11.85/14.25 GHz. The proposed structures maintain low-cost and mass producible characteristics of E- plane waveguide filters while achieving significant size reduction.

REFERENCES

[1]Vicente E. Boria and Benito Gimeno, “Waveguide Filters for Satellites” IEEE Microwave Magazine, Vol.8, Issue 5, pp.60-70, October 2007.

[2]Ian C. Hunter, Laurent Billonet, Bernard Jarry, Pierre Guillon, “Microwave Filters—Applications and Technology” IEEE Trans. Microwave Theory Tech.,Vol.50, pp. 794-805, Mar. 2002.

[3]D. Budimir, "Generalized Filter Design by Computer Optimization", ISBN 0-89006-579-9, Atrtech House Books, 1998.

[4]G. Goussetis, and D. Budimir, " Compact Ridged Waveguide Filters with Improved Stopband Performance”, IEEE MTT-S International Microwave Symposium, pp.953-956, June 8-13, 2003, Philadelphia, USA.

[5]Microwave Studio, CST, 2010