Abstracts:Theoretical and experimental investigations on isosceles 45°–45°–90° Triangular Dielectric Resonator Antenna (TDRA) is presented here for ${\mathit{TM}}_{\mathit{mnp}}^{\mathit{z}}$ modes. Approximate expression is given here to predict the resonant frequency for different ${\mathit{TM}}_{\mathit{mnp}}^{\mathit{z}}$ modes with an accuracy of 2.3%. It is found that isosceles 45°–45°–90° TDRA radiates in the broadside direction at fundamental ${\mathit{TM}}_{\mathbf{101}}^{\mathit{z}}$ mode. One prototype is also fabricated to validate our theory. It is also found that the fundamental ${\mathit{TM}}_{\mathbf{101}}^{\mathit{z}}$ mode produces slanted polarization. The study of 45°–45°–90° TDRA is important as it just takes approximately half volume compared to square Dielectric Resonator Antenna (DRA) for a given resonant frequency. Our theory can easily be extended to design filter, oscillator etc.

Abstracts:This paper presents the design of a compact, high selectivity and wideband bandpass filter based on signal interference technique. The proposed filter consists of open coupled line and stepped impedance modified Π-type (SMΠ) transmission line with short circuited stubs in transmission path 1 and path 2, respectively. Due to the superposition of signals of the two transmission paths, a fourth-order wideband bandpass filter with six transmission zeros can be obtained from 0 to 2$f_0$ ($f_0$ is the operating frequency). A bandpass filter prototype centring at 0.9 GHz, with 3 dB fractional bandwidth of 50% is designed, fabricated and tested. Good agreement is found between the simulated and experimental results.

Abstracts:This paper presents quadrature oscillator and universal filter based on translinear current conveyors. The proposed circuit can realize as a quadrature oscillator or a universal filter without changing the circuit topology. When it works as a quadrature oscillator, four quadrature current outputs and two quadrature voltage outputs can be obtained. The condition and frequency of oscillation of oscillator can be controlled orthogonally and electronically. When it works as a universal filter, low-pass, band-pass, high-stop, band-stop, and all-pass filtering functions can be obtained simultaneously. The natural frequency and quality factor of filters can be controlled orthogonally and electronically. The proposed topology is simulated using PSPICE simulators and experimental results are also used to confirm workability of new circuit.

Abstracts:Chaotic and hyperchaotic systems with interesting behaviors have been of interest in the recent years. In this paper we introduce a hyperchaotic memristor oscillator which shows both stable and unstable fixed points. Such systems have been less investigated in the literatures. It should also to be noted that the proposed hyperchaotic system has only one nonlinearity which is a flux controlled memristor. Depending on the control parameter, the system displays different behaviors and coexisting attractors. A linear quadratic regulator based synchronization of the proposed hyperchaotic system is designed and numerically analyzed. We also design such a fuzzy based PID controller for chaos control in such a memristor oscillator.

Abstracts:A compact hexagonal nested loop antenna with hexagon dumb bell shaped defected ground structure is proposed for quad band wireless application. Effects of fractal iterations and position of dumbbell defect on ground plane are optimized for wideband characteristics and better performance of the antenna. An equivalent circuit of the proposed antenna and defected ground structure (DGS) is modelled and the same is verified using ADS. Reflection coefficient and radiation properties further confirm the performance of the proposed design for wireless applications. The proposed design is fabricated on FR4 substrate with an overall dimension of 40 × 32 × 1.6 mm³. Simulated results are validated by proper measurement and are in good agreement with experimental results.

Abstracts:A compact ultrawideband multiple input multiple output antenna with dual band notch characteristics is proposed. The design utilizes the property of quasi-self-complementary monopoles to achieve a bandwidth that ranges from 2.2 GHz to 11 GHz. The design has a compact size of 30 mm × 41 mm × 1.59 mm. Two quasi-self complementary half circular monopoles are symmetrically arranged to obtain MIMO antenna. Bandnotch characteristics are obtained by adding parasitic strips of Levy's Fractal shape near the feed line. A Hilbert Fractal shaped slot is etched in the ground plane to enhance the isolation (|S21| < −20 dB) throughout the operational bandwidth. The measured and simulated radiation patterns are in good agreement and is found to be stable throughout the ultrawideband. Moreover, the measured peak gain is found to be 4 dBi.

Abstracts:This paper presents a new third-order RLCM-four-elements-based chaotic circuit, in which the memristor element is equivalently implemented by a diode-bridge cascaded with an inductor. Mathematical model is established and its equilibrium stability is analyzed. The dynamical properties of the memristive chaotic circuit are disposed by MATLAB numerical simulations and confirmed by breadboard experimental measurements. In particular, the antimonotonicity phenomena of coexisting periodic and chaotic bubbles are observed under some specified control system parameters and the evolutions of coexisting bubbles are exhibited with the variations of two control system parameters. The presented memristive chaotic circuit is very simple and only third-order but can emerge complex dynamics with chaos, period, coexisting bifurcation modes, and coexisting bubbles.

Abstracts:This paper presents an approximate solution of a 2D Poisson’s equation within the channel region for Double-Gate AlInSb/InSb High Electron Mobility Transistors (DGHEMTs), using variable separation technique. The proposed model is used to obtain the surface potential, electric field, threshold voltage and drain current of both tied and separated gate bias conditions for Double-Gate AlInSb/InSb HEMTs. The surface potential and electric field are derived for both effective conduction paths of front and back heterointerface by a simple analytical expression and an analytical solution is verified with sentarus TCAD device simulator.

Abstracts:A dual-band microstrip patch antenna with copper reflector plate, and high gain for LTE and wireless communications applications is presented. The proposed antenna consists of an FR4 substrate which is kept by Teflon spacers at a specified distance from the reflector plate. The bottom layer of substrate includes two identical C-shaped dipoles, and the top layer contains irregular microstrip lines which are excited using a coaxial cable. This antenna operates in two frequency bands of 1.5–2.8 GHz and 5–5.9 GHz with gains of ∼5.5 dBi and ∼5.7 dBi, respectively. Also, it has a unidirectional radiation pattern, wide HPBW, and F/B ratio of over 12.5 dB in both frequency bands.

Abstracts:Energy conservation is a critical issue in resource constraint wireless sensor networks. Employing mobile sink to deliver the sensed data becomes pervasive approach to conserve sensors’ limited energy. However, mobile sink makes data delivery a hard nut to crack since nodes need to know its latest location. Providing sink’s latest location by traditional flooding, erode the energy conservation goal. In this paper, we propose a Grid-Cycle Routing Protocol (GCRP) with the aim of minimizing the overhead of updating the mobile sink’s latest location. In GCRP, sensor field is partitioned into grid of cells and for each cell a grid cell head (GCH) is elected. Cycles of four GCHs is formed. Cycle(s) involving border GCHs is called exterior cycle and said to belong to a region. Another cycle involving non-boundary GCHs is called interior cycle, connecting GCHs of different regions. When sink stays at one location, it updates the nearest GCH, which in turn updates the other GCHs through exterior and interior cycle. Moreover, we propose a set of sharing rules that govern GCHs when and with who share sink’s latest location information. The performance of GCRP is evaluated at different number of nodes and compared with existing work using NS-2.31.