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This paper describes the design, development and performance of coaxial cavity band pass filters for transmit and receive chains of Standard-C terminal of International Maritime Satellite (INMARSAT) system.The band pass filters are at centre frequencies 1537.5 & 1636 MHz with bandwidths of 15 & 20 MHz with respect to centre.The sharp cut off has been achieved at 1626 & 1545 MHz for receive...
A high power amplifier has been developed for the RIB program, where in a typical 1 kW triode based amplifier drives a high power 40 kW (CW) radio frequency amplifier for the frequency range of 32 MHz to 39 MHz. This driver amplifier has been realized in grounded grid configuration. The analysis of this amplifier has been carried out using ABCD parameters method. It uses a linear small-signal AC model...
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.
In the present work, polycrystalline ferromagnetic Zn0.95Co0.05O samples have been synthesized in a TM011 single mode cylindrical microwave resonant cavity operating at 2.45 GHz. The synthesized specimen is analyzed for its crystallographic and electronic structure along with magnetic and electron transport properties. The X-ray diffractogram and photoelectron spectroscopy of Zn0.95Co0.05O establish...
A variable high power microwave system, wherein output power can be varied from 0.6 kW to 5 kW at a nominal frequency of 2450 MHz has been designed and developed for processing of material in liquid form. Two applicators have been developed for the processing of material. One is a rectangular multimode cavity for batch processing. The second one is cylindrical cavity with tubes for continuous operation...
In the present communication a new method for calculation of various parameters of an annular ring antenna is proposed using extended cavity model. The model is easier and intuitive than the full wave analysis. The properties of return loss, radiation pattern and quality factor of ring antenna are calculated and compared with the simulated results of the existing model.
This paper deals with the study of the gyrotron cavity for its cooling. Cavity with different types of groove structures and their thermal effects have been studied to optimize cooling effect.
Gyrotron is a high power microwave device intensively developed for heating of plasma in thermonuclear fusion research. The relativistic gyrating electron beam interacts with transverse electric (TE) wave near cutoff in a uniform section of tapered cavity resonator at a DC magnetic field helps to excite several modes simultaneously. The efficient operation of the gyrotron requires excitation of desired...
In this paper we will report analysis of a quantum-well (160 Aring QW) Transistor Laser with 150 mum cavity length using a charge control model in order for modifying QW location through base region. The analysis shows significant enhancement, at constant bias currents, in optical bandwidth due to moving the QW in the direction of collector-base junction. No remarkable resonance peak, limiting factor...
In this paper measurement of real part of permittivity and loss tangent of Zn1-x Mgx TiO3 (ZMT) ceramics in S-band of microwave frequencies is presented and the associated accuracy estimated. This approach is based on the measurement of transmitted power from the cavity at and off resonance. Details of the design and fabrication of the rectangular cavity and the input and output coupling are given...
A study has been made while analyzing an unusual problem in linear accelerator system, wherein, klystron has been used as high power microwave source. Klystron output started dropping unexpectedly for which, diagnosis was made. The root cause of the problem was found to be presence of corrosive sulfur in insulating oil used. Mineral oils are very commonly used as electrical insulation. This paper...
Defected ground structures (DGS) have been developed to improve characteristics of many microwave devices. Although the DGS has advantages in the area of the microwave filter design, microstrip antenna design for different applications such as cross polarization reduction and mutual coupling reduction etc., it can also be used for the antenna size reduction. The etching of a defect in the ground plane...
There is a growing concern about the effect of electric and magnetic fields in the microwave range frequencies on human health. The common microwave oven emits radiation in the frequency region of 2.45 GHz. On the other hand RF radiation (~27 MHz to 1 GHz, microwave diathermy) is beneficially used in physiotherapy for muscular relaxation. There are weapons based on microwave beams and microwaves are...
Electromagnetic fields in the microwave frequency have been used to sort good seeds from the bad ones and the technique makes use of the absorptive component of the dielectric constant of the water molecules material in this frequency region. On the other hand, microwaves are also used for accelerating the culture growth of a bacterial medium. One theory holds that the beneficial effects of microwave...
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...
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