Waveguide Model Method Research Articles

Sierpinski Carpet Patterned Rectangular Dielectric Resonator Antenna for X-Band Application Using Teflon

This paper presents a wideband Sierpinski carpet fractal patterned rectangular Dielectric Resonator Antenna (DRA) operating in the X-band, which is characterized by dielectric waveguide model method (DWM). In order to decrease the cost of the DRA the low-cost teflon is used as the material. A prototype is realized to validate the results of the simulation. The paper provides a comparison between conventional rectangular DRA and fractal shaped rectangular DRAs of the first and the second iterations. The antenna design methodology is discussed along with its resonance and radiation characteristics. The validity of the obtained results is proved by the close match of the experimental and simulation results. The measurements on prototype show impedance bandwidth of 48% covering the entire X-band with similar radiation pattern throughout the band with a gain of 7.5 dBi over 9.0–11.5 GHz.

Investigation of higher order modes excitation through F-shaped slot in rectangular dielectric resonator antenna for wideband circular polarization with broadside radiation characteristics

In this article, a wideband circularly polarized rectangular dielectric resonator antenna (RDRA) with broadside radiation characteristics has been proposed. By using modified ground plane having an F-shaped slot, the proposed structure able to generates three sets of modes i.e., fundamental as well as higher order modes. To obtained circular polarization, an orthogonal mode (TE113) in the RDRA has been generated by using the F-shaped slot on the modified ground plane. The resonance frequency of fundamental mode (TE111) in the rectangular dielectric resonator (DR) has been calculated by using dielectric waveguide model method. The same has been confirmed through E-field distribution in RDRA. Here, wide axial ratio (AR) bandwidth of the proposed antenna is due to the generation of and modes. It is observed that input impedance bandwidth has been broadening with a pair of excited modes ( and modes) in the proposed antenna structure. All these modes have been excited and merged to form a wide input impedance bandwidth and wide AR bandwidth of the designed antenna. The proposed antenna shows measured input reflection coefficient (S11 < −10 dB) of 50.55% and measured AR bandwidth (AR < 3 dB) of 14.28%. The designed antenna shows left-handed circular polarization in broadside direction and offering an average gain and radiation efficiency of 4.29 dBic and 92.22% respectively.

Waveguide model of the hearing aid earmold system

BackgroundThe earmold system of the Behind-The-Ear hearing aid is an acoustic system that modifies the spectrum of the propagated sound waves. Improper selection of the earmold system may result in deterioration of sound quality and speech intelligibility. Computer modeling methods may be useful in the process of hearing aid fitting, allowing physician to examine various earmold system configurations and choose the optimum one for the hearing aid user.MethodsIn this paper, a computer model adequate for this task is proposed. This model is based on the waveguide modeling method. The waveguide model simulates the propagation of sound waves in the system of cylindrical tubes. Frequency response of the hearing aid receiver is simulated in the model and the influence of the ear canal and the eardrum on the earmold system is taken into account. The model parameters are easily calculated from parameters of a physical hearing aid system. Transfer function of the model is calculated and frequency response plots are obtained using the Matlab system.ResultsThe frequency response plots of the earmold model were compared to the measurement plots of the corresponding physical earmold systems. The same changes in frequency responses caused by modification of length or diameter of a selected waveguide section, are observed in both measurement data of a real earmold system and in computed model responses.ConclusionComparison of model responses obtained for various sets of parameters with measurement data proved that the proposed model accurately simulates the real earmold system and the developed model may be used to construct a computer system assisting the physician who performs earmold system fitting.

Quasi-optical waveguide modeling method and microcompact scattering range for the millimeter and submillimeter wave bands

The possibility of using the quasi-optical waveguide modeling (QWM) method in the near millimeter and submillimeter ranges of the electromagnetic spectrum for a study of the backward and forward scattering amplitude and phase characteristics of physical objects or scaled models is discussed in the paper. The method is realized with the aid of a quasi-optical waveguide microcompact range (MCR). The microwave part of MCR is based on the regular section of a hollow dielectric waveguide (HDW) and corresponding quasi-optical components. The results of measurements of backward and forward scattering characteristics for a number of standard objects in the 4-mm wavelength band are presented.