DESIGN AND ANALYSIS OF SUN-SHAPED LPF USING CSRR

Abstract

Metamaterials are artificial metallic structures having simultaneously negative permittivity (ɛ) and permeability (μ), which leads to negative refractive index. Due to negative index it supports backward waves i.e. inside Metamaterial phase velocities and group velocities are antiparallel. Metamaterial doesn’t obey Snell’s law, Doppler effect, Vavilov-Cerenkov radiation etc. No other material in the world shows the above properties like Metamaterial. Due to these unusual properties Metamaterial can change the electric and magnetic property of electromagnetic wave passing through it and because of these reasons when Metamaterial is used in the fabrication of microwave components and antennas the required properties can be enhanced. Also miniaturization in the size of the component is possible as the structural cell size of Metamaterial is less than one-fourth of the guided wavelength. With the basic knowledge of metamaterials where used to design a LPF using sun-shaped CSRR. In microwave systems, LPF is regularly used to get rid of the undesired frequency. Step impedance low-pass filter and open stub low pass filter are generally utilized for this reason. Yet these low pass filter have steady cut-off response. By expanding the number of areas, the rejection characteristics can be better. However, by expanding the number of sections, the pass-band insertion loss increases and also the physical size of the overall filter increase. A few strategies have been accounted to tackle this issue. So a new artificial material is used which is known as metamaterials, using the properties of these unique properties a compact size filter can be designed. The designed LPF using sun-shaped resonator with eight slot of equal size at equal distance from each other has been designed. This designed filter has low insertion loss and sharp cut of frequency at 1.69 GHz. The low pass filter was designed on a FR-4 (lossy) substrate with a height of 1.6mm and the relative permittivity of 4.30. The filter designed has eight slots of equal size giving a sun shape which are etched on the ground plane of the substrate. The designed filter has low pass band insertion loss and a sharp cut off frequency at 1.69 GHz. Thus a sun shaped low pass filter with compact size is designed and simulated in CST Microwave Studio. The low pass filter is fabricated and tested to verify the results attain from the simulation. This designed filter can be utilized in microwave to reject the undesired frequency in microwave systems. Moreover the designed low pass filter is compact and small in size vi

as compared to the conventional low pass filters designed which makes a component more efficient and helps in future technology for making miniaturized components for wireless communication. Due to size miniaturization of the components, more and more number of filters can be fabricated in a small region to lessen the cost and material utilized for the last fabricated microwave components.