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In this work, a three-dimensional (3D) simultaneous arbitrary-way orbital angular momentum (OAM) generator is presented. The proposed generator is constructed by a group of transformation cylinders filled with metamaterials. Using transformation cylinders, arbitrary-way planar wave fronts can be simultaneously converted to helical wave fronts with arbitrary topological charges. Firstly, the principle...
This paper presents a novel spurious coupling compensation technique for coax cavity resonator based filters. It has been found that cross coupled coax cavity filter suffers from the problem of spurious coupling between non-adjacent resonators which leads to asymmetric transmission response and group delay characteristics, which, in turn leads to deterioration in the RF performance. An exhaustive...
A compact bandpass filter having an ultra wide pass band (UWB − 3.1 to 10.6 GHz) is proposed. It is based on hybrid microstrip coplanar waveguide (dual sided metal) structure. A Multiple Resonant Structure (MRS) is constructed using coplanar waveguide (CPW) planar transmission line. The MRS makes the resonance using quarter wavelength and half wavelength open ended CPW. The equispaced three resonances...
A cuboid metamaterial unit cell with μ = −1 is presented. A periodic configuration consisting of the proposed 3D unit cell is realized for magnetic field focusing application. The unit cell of subwavelength consists of capacitor loaded planar printed rings on each face of cuboid of dimension 15×15×16mm3. The unit cell is designed by considering the effect of capacitor's tolerance on the resonant frequency...
The effects of stationary clutter on moving target detection radar are analyzed by simulations. Radar with pseudo random binary sequence (PRBS) based probing signal is utilized as moving target detection radar in the simulations. And results in case of target return and clutter show that stationary clutter does not disturb hardly the moving target detection, as long as below two points are fulfilled...
A novel dual-layer Jerusalem-shaped element is proposed to design a circularly polarized reflectarray with a linearly polarized horn antenna. The proposed element shows an almost linear behavior and more than 500° phase variation. A 90° relative phase shift is generated by adjusting the arms of the element independently. Among these, a 316-element circular aperture reflectarray is investigated on...
A compact symmetric/asymmetric CPW feed UWB antenna with polarization diversity characteristic is presented. The proposed structure consists of two orthogonally placed UWB antennas. One of the antenna elements in the proposed structure is feed with symmetric CPW feed while another antenna is feed with asymmetric CPW feed. The proposed feeding techniques minimize the mutual coupling (≤ 20dB) between...
Synthetic Aperture Radar sensors are very sensitive to changes in soil moisture and surface roughness, making SAR useful for characterizing long-term post-fire patterns/trends. The present study has analyzed and quantified forest burnt areas of selected fire prone ecosystems i.e. Nallamalais of Andhra Pradesh and Part of Tripura, India. RISAT-1 data pertaining to pre and post fire were utilized. Encouraging...
A microstrip line fed star fractal antenna for super wideband applications is presented. Second iterative star shaped fractal geometry of the radiator, modified feedline and notch loaded semi-elliptical ground plane are used to achieve an impedance bandwidth of 4.6–52 GHz. A good agreement is observed between the simulated and experimental results. It has an overall volume of 19.7×19×1.6 mm3. It has...
Spoof Surface Plasmon (SSP) modes have been of great interest in designing low loss and single-layer transmission lines and other microwave components. These slow-wave structures have great potential to form high efficient and single layer antennas; however, their conversion to fast propagating waves has not attracted much attention so far. This paper exploits the spoof surface plasmon modes to design...
In this paper, a 30W-class X-band high-efficiency Internally Matched FET (IMFET) implemented in a 0.15 µm GaN HEMT process is presented. The fabricated HPA has achieved the Pout of 28–31.5 W and the PAE (power added efficiency) of 57–60% and the gain of 11–12.5dB over 8% relative bandwidth. To the authors' knowledge, this is one of the highest level performance among ever-reported ones.
This article presents a dual band metamaterial absorber suitable for applications over the WLAN and Wi-MAX frequencies on a metal-backed FR-4 Epoxy substrate utilizing a novel I-shaped unit cell structure for the design. The component shows dual band absorption at frequencies 3.5 GHz and 5.8 GHz respectively with 100% absorption of the incident signal at both the points of observation. The component...
In this paper, a new time-domain (TD) diffraction coefficient for non-perfectly conducting wedges is proposed that is applicable to the case when the source illuminates either one or both sides of wedge for different wedge angles. The TD received field is compared with the inverse fast Fourier transform (IFFT) of frequency-domain (FD) solution. Finally considering hard polarization, the computational...
A dual-band balanced bandpass filter (BPF) is proposed using stub-loaded resonators. Based on the theoretical analysis, it is found that the electrical performances of the differential-mode (DM), such as center frequencies and bandwidths can be controlled independently. The center frequency ratios of the two DM passbands can range from 1 to 2.6. The resonant frequencies of the common-mode (CM) are...
A 1GHz Wilkinson power divider utilizing phase shifted transmission line sections to replace the quarter lambda sections is presented. The phase shifted transmission line section are composed of several high impedance and low impedance transmission lines to mimic conventional π-type lumped inductor (L) capacitor (C) phase shifters. A rectangular-shape Defected Ground Structure (DGS) is used to implement...
A dual-band dual-polarized CPW-fed slot antenna for WLAN applications is presented. The antenna shows two resonant dips at 3.56 GHz and 5.12 GHz. For the WLAN band (3.6 GHz) the antenna shows a circularly polarized behavior, whereas in case of the other band it is acting as a linearly polarized component. The design geometry consists of a CPW-fed thin slot structure with an LC complimentary resonator...
In this paper, novel two loop architecture of ring type voltage controlled oscillator (VCO) with low phase noise and low power dissipation in 0.18 µm CMOS technology is presented. To reduce phase noise and power dissipation, transistors in sub-feedback loop are operated in linear and cut off region and transistors in main loop of inverter are designed for fast switching with large voltage swing to...
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