Showing papers by "Kumar Vaibhav Srivastava published in 2010"

Multi-layer multi-permittivity dielectric resonator: A new approach for improved spurious free window

Abstract: In this paper, a novel approach has been suggested to get spurious free window of dielectric resonator (DR) in MIC environment. In MIC environment, due to smaller thickness of substrate with respect to cavity dimension, the position of DR becomes asymmetric within the cavity. Due to this asymmetry, the field configuration of resonance mode modifies from its symmetry value and mode separation gets reduced. This asymmetry is compensated by introducing the different layers in DR, called as multilayer DR, with each layer having different permittivities. The multilayer makes the DR asymmetric with its axial direction and helps to compensate the asymmetry due to its position, and improves the mode separation. The results shows that multilayer ring DR gives always improved separation over the ring DR for all the range of substrate thickness.

An investigation on three element multilayer cylindrical dielectric resonator antenna excited by a coaxial probe for wideband applications

Abstract: The main objective of the present study is to improve the bandwidth of the dielectric resonator antenna (DRA). A new three-element multilayer cylindrical dielectric resonator antenna (MCDRA) array above the ground plane is proposed here. MCDRA is easy to design and excited with HE 11dδ mode excited in each MCDRA by centrally placed dielectric resonator in which TM 01dδ mode excited. The effect of design parameters such as permittivity of materials, probe height and arrangement of dielectric layers are investigated and the excited modes (i.e. TM 01dδ and HE 11dδ ) are also been confirmed by simulations. The simulation is performed on Ansoft's HFSS package. The proposed multilayer cylindrical dielectric resonator antenna (MCDRA) can offer an impedance bandwidth of ∼47% for the return loss below −10dB where frequency range is from 4.5 to 6.8 GHz and resonance frequency is 4.91 GHz with monopole like radiation pattern and it is stable in the passband with 5.06 dB gain.

Compact two pole bandpass filter using symmetrical composite right/left handed transmission line with vias

Abstract: A compact two-pole bandpass filter based on the composite right/left-handed (CRLH) metamaterial transmission line structure is proposed in this paper In detail, subwavelength resonators are realized through the zeroth order resonance (ZOR), and inverter structures are proposed to control the coupling between neighbouring ZOR resonators The proposed technique is validated by the EM predictions, the proof of metamaterial properties with the ZOR field distributions and extracted constitutive parameters, and measurements Size independent resonance property of the ZOR combined with homogeneity condition of the LH TL unit cell is utilized in the size reduction of bandpass filter It is found that the suggested method enables the remarkable size reduction from the conventional filters such as the parallel coupled type which is designed on the basis of the half-wavelength resonance The proposed technique is also validated by the experimental results

A 600MHz, 6 th order, highly linear Gm-C bandpass filter design

Abstract: A highly linear 600 MHz centre frequency, 500 MHz bandwidth 6th order Butterworth bandpass filter using a Leap-Frog Gm-C topology is designed. Fully differential inverter based Operational Transconductance Amplifier (OTA) with common-mode feedback (CMFB) and common-mode feed forward (CMFF) circuit is used in the design. Cadence tool has been used on IHP SiGe BiCMOS 0.25 µm node. The filter consumes power of 44.87 mW.