Journal of Electromagnetic Analysis and Applications, 2012, 4, 423-425

http://dx.doi.org/10.4236/jemaa.2012.410058 Published Online October 2012 (http://www.SciRP.org/journal/jemaa) 423

Effect of the Width of the NRD Waveguide on the S

Parameter of a Pass Band Filter

Harizi Hanen1, Lattrach Lassaad1, Gharssallah Ali1, Garbi Abdelhafedh2

1Unit of Research Circuits and Electronics Systems High Frequency, Faculty of Science, University El Manar, Tunis, Tunisia;

2Laboratory of Research Circuits and Electronics Systems High Frequency, Faculty of Science, University El Manar, Tunis, Tunisia.

Email: hanenharizi@gmail.com

Received July 9th, 2012; revised August 18th, 2012; accepted September 3rd, 2012

ABSTRACT

In this paper, we present a design of a non-radiative dielectric waveguide band pass filter based on hybrid architecture

of micro-strip line and non-radiative dielectric waveguide. The simulation with high frequency structure simulator

(HFSS) three dimensional analyses are presented, also the influence of the feeding transitions for circuit design is studied .

The aim of this work was to study the influence of the width of the NRD waveguide to scattering parameters.

Keywords: Non Radiative Dielectric (NRD)

1. Introduction

The technology demand to realize high efficiency circuit,

but productions cost extremely high. Designed for milli-

metre wave, active circuits use planar technology and

passive circuits employ waveguide technologies to inte-

ger those two technologies require highly accurate as-

sembly thus increasing production cost and time. To de-

crease it, the non radiative dielectric waveguide technol-

ogy should be used.

A non-radiative dielectric waveguide is currently in-

teresting filter types due to their high Q at low cost tech-

nology for fabrication and compatibility with other tech-

nology.

Hence their electromagnetic models are still under re-

search and therefore not easy accessible. This work aims

to provide circuit designers with accurate, easy deter-

minable for a pass band filter.

Proposed by Yoneyama and Nishida in 1981 [1], non-

radiative dielectric (NRD) waveguide circuits is nowa-

days a well-known technology for various millimeter-

wave applications [2,3]. Subsequently, Bacha has pro-

posed the model of a hybrid integration of NRD-

waveguide and micro-strip line [4,5]. Indeed, basic fea-

tures and applications of the NRD-waveguide had been

investigated by different research, since it permits to ex-

ploit inherent advantages of planar structures and NRD

waveguide for low cost microwave application. However,

several techniques wer e proposed, Grigoropoulos and Young

present a non-radiative perforated dielectric (NRPD) in

[6], Cassivi and Wu introduce the substrate integrated

non-radiative dielectric (SINRD) [7]. Other scheme of

design called engraved non-radiative dielectric waveguide

(ENRD), proposed to reduce the problem of alignment

and mechanical tolerances in fabrication of NRD com-

ponents, this design was described in [8,9].

The reference [10] presents the design of pass band

filter in hybrid architecture planar/non radiative dielectric

wave guide integration technology and shows parameters

S. In order to optimize the results of this work, we

thought to var y the width of the N RD gu id e and show th e

influence of this variation.

2. Theoretical Approach

Its basic component, the NRD waveguide consists of a

rectangular-section dielectric rod sandwiched between

conducting plates that are at a distance apart less than

half the free-space wavelength, the thickness is b and the

relative dielectric constant is r

which must be superior

to the relative dielectric constant of the border dielec-

tric.

To express the principle of operation mathematically,

we will consider a straight strip as shown in Figure 1;

the required distance between the two metallic plates of

NRD wave guide is computed using the following rela-

tion:

0

2r

a

where 0

the free-space wavelength r

the relative

dielectric constant.

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