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In this paper an analytical formula for the measurement of the dielectric constant of materials having cylindrical shape is derived using cavity perturbation method. The formula is established using two known samples Teflon and Perspex at X-band frequencies and the results are compared with those obtained for rectangular samples.
This paper deals with the study of pillbox type dielectric window for X-band linac which is capable of handling average and peak powers of 2 kW and 2 MW, respectively, at spot frequency 9.4 GHz with VSWR and insertion loss of 1.1 and 0.1 dB, respectively. The HFSS software is used for computation of length of window, diameter and thickness of dielectric used for window. The theoretical values of VSWR,...
Summary form only given. The recent rapid progress in microwave communication accelerates the search of new materials to meet the present challenging performance requirements. In order to maintain high signal conveying efficiency, the dielectric substrate should have low relative permittivity and low dielectric loss. Several low loss low permittivity ceramics such as silicates and aluminates have...
The paper discusses the design of dielectric rod antenna at D band which can be used as a feed for dielectric lens antennas. This feed replaces the metallic corrugated / dual mode horns which are difficult to fabricate at these frequencies. Tapering of dielectric rod has been done to achieve low side lobe level. The designed antenna has been simulated on 3D EM software HFSS (high frequency structure...
Tunable materials are those whose dielectric constant is dependent on a dc bias electric field. This property is a primary hallmark of ferroelectrics. Because of the loss issues, instead of in the ferroelectric state, this property is exploited in their paraelectric phase eventhough the tunability is slightly lower. Apart from these materials there are other oxides and biopolymers which are known...
Dielectric windows often limit the power handling capability of vacuum electron devices. It is necessary to choose the right dielectric material for high power applications. Depending upon the power level, a range of materials has been used in various systems. The ideal material should have high mechanical strength, high thermal conductivity, high electrical breakdown voltage, low dielectric loss,...
A cavity perturbation technique is presented for measurement of dielectric constant and dielectric loss of the dielectric materials at X-band microwave frequency. A tunable rectangular cavity to operate in TE103 mode was designed and fabricated. Tunable cavity is calibrated to read its resonance frequency directly from the micrometer screw arrangement attached with the cavity. Shift in resonance frequency...
A new wideband small size Crescent Slot Ellipse Shape Antenna (CSESA) with crescent slot is presented. A lossless material honeycomb dielectric of dielectric constant 1.11 is sandwiched between radiating patch and ground. The proposed antenna is excited by coaxial probe excitation technique. The main motivation for this work is to enhance the bandwidth of the Impedance. The simulation results verify...
This communication a microstrip array antenna consist of 16 rectangular patches work as a signal to noise enhancer in L-band of microwave frequency is proposed. This array geometry proposed on YIG substrate which works on the principle of inverse dynamic nonlinearity of Magnetostatic waves in ferrite substrates. The simulated radiation patterns and computed values of resonance and cutoff limit is...
The paper presents a modified rectangular patch microstrip antenna having a triangular notch in one of its straight arm and designed on dielectric material under the presence of variable air gap. The measured performances of this antenna without air gap are compared with those obtained through simulation results of this antenna under the presence of variable air gap. It is observed that the performance...
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