Dhirendra Kumar

An application of fractal geometry to design the microstrip circuits

The fractal geometries such as Koch curve, Sierpinsky gasket, and Hilbert curve, etc. have been widely studied and applied to design several microwave devices, such as antennas, frequency selective surfaces (FSS), and photonic band gap (PBG) devices. There are several advantages of these fractal devices including reduction of resonant frequencies, smaller size and broadband width. In this paper a critical study has been presented on application of fractal geometry to design the microstrip antenna, microstrip filters and frequency selective surfaces.

Compact ultra wide band filter using triangular patch resonators

A compact ultra wide band pass filter has been proposed in this paper. The band pass operation of the filter has been obtained with the combinations of high pass filter and low pass filter. The low pass filter used in the combined structure is designed using the triangular patch resonators and the high pass filter is designed using shorted stubs. The three different topologies to combine the low pass and high pass filter are compared. The final structure gives a very compact configuration of ultra wide band pass filter. The design methodology of the proposed filter is elaborated. The designed structure is simulated and fabricated. The group delay of the filter gives almost flat for the entire operation band. A good agreement has been seen between simulated and measured values of scattering parameters. The fractional band width has been achieved as 130%.

Single pole compact narrow band pass filter using periodic ground defects

In this paper a compact narrow band pass filter has been designed. An H-shape section of microstrip is used to get the smaller band width. The parallel lines are connected to the H section. The periodic slots are made on the ground plane of the microstrip. These defects cause the circuit more compact. The filter has been designed for center frequency 4 GHz and fractional band width 3%. The design methodology has been clearly explained. To verify the proposed technique, a filter has been fabricated and tested. Amoderate matching of the results between the measured and simulated results has been observed due to some imperfection in fabrication.

Design of Compact Low Pass Microstrip Filter For Wireless Communication System

Abstract A compact microstrip low pass filter has been designed using step impedance technique. Two slots were cut in the ground plane just below the high impedance microstrip lines. The proposed filter has spurious free response for wide band width with sharp cut-off characteristics. The filter has been designed for a cutoff frequency 2.5 GHz and provides good agreement between the simulated and measured results.

Transmission characteristics of rectangular dielectric guide in the millimeter wave region with embedded metallic discontinuities

In this paper, the investigations of the rectangular dielectric waveguides with embedded metallic discontinuities in millimeter waves (70–130 GHz) region have been presented. The full wave simulation of the structure has been carried out using frequency division time domain method. The frequency response of the structure shows that it can be used in designing of a dielectric filter in the given frequency range. The graphical representations of scattering parameters have been given for different values of the height of the dielectric rod and for the changes in the permittivity of the rod.

An effective design of parallel coupled microstrip band pass filter without the spurious bands

Parallel coupled microstrip filters are extensively used as band pass filter in microwave communication because they are compact in size, easy to fabricate due to its planar structure. The responses of these filters are satisfactory for narrow bandwidth due to their relatively weak coupling. A severe limitation of the conventionally designed parallel coupled filters is parasitic response at harmonics. In this paper some techniques are discussed to minimize the spurious bands, and also an effective design to suppress these spurious pass bands has been proposed.