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This paper presents a novel design of negative group delay circuit (NGDC) with very low signal attenuation (SA) and multiple-poles in group delay (GD) characteristics. The very low SA is obtained due to high characteristics of coupled lines. Theoretical analysis shows that the multiple-poles in GD characteristics can provide wider negative GD bandwidth and be obtained by connecting coupled lines resonators...
This paper presents a novel structure for ultra broadband 4∶1 broadside-coupled PCB impedance transformer. Analysis, simulations and measurements of the developed transformer are introduced and discussed. Three prototypes of the proposed structure are implemented at center frequencies 5.65 GHz, 4.35 GHz and 3.65 GHz, respectively with fractional bandwidth of greater than 180 %. The implemented transformers...
A novel design of millimeter-wave antennas integrated with a high-impedance surface (HIS) reflector is presented within the particular context of 3D heterogeneous integration on silicon interposer an its specific requirements. Then, the design steps of a 60-GHz folded dipole antenna for short-range communications are detailed. Simulation and measurement results show promising performances in terms...
The demand for a software-defined radio (SDR) is increasing because it can support variety of frequency bands and modulation techniques. However, a condition of an antenna can become a bottleneck of the communication system using SDR due to less flexibility of the antenna. For example, when the SDR changes the signal frequency dynamically or the communication system faces a disturbance such as human...
A novel wideband balanced power dividing/combining network is proposed in this paper. Based on matrix transformation, the differential mode and common mode equivalent circuits of the wideband balanced network can be easily deduced. A planar wideband balanced network with bandwidths of 55.3% (|Sdd21, 31| < 4 dB) for the differential mode with wideband common mode suppression is designed and fabricated...
A high ratio Wilkinson power divider is produced by cascading low ratio dividers. Combining two 1∶2 and one 1∶3 divider results in a 1∶8 ratio. Theoretically the 1∶8 divider has an S21 of −0.51dB and an S31 of −9.54dB. Under simulation the average S21 over a 1.7–2.7GHz band was −0.7dB and the S31 −10.3dB. A prototype was built on standard 1.6mm FR4 substrate. The 1∶3 divider uses stacked substrates...
A new quad mode 2-way Microstrip reconfigurable power divider is presented. The proposed power divider, through the use of 4 or 6 switches, can alternate the operating mode between a total of 4 modes. The four operating modes are: totally directing the power into one of the two output ports (1∶0) & (0∶1) and two-way equal power split with + or − 90o phase shifts (1∶j) & (j∶1). Several dividers...
This paper investigates the feasibility of direct and forward links for UHF-RFID tags implanted into human limbs when interrogated by a non-contacting reader's antenna. Performance gain indicators of the through-the-body RFID channel are estimated by electromagnetic simulations over an anthropomorphic phantom as well as by means of experimentation with a real RFID communication link involving a simplified...
A simple method for designing and determining the impedance taper of a smooth conical to coaxial transmission line transition is presented. This type of transition is often used in conical line combiners and traditionally has a constant impedance. The presented method allows the conical and coaxial lines to be designed with different impedances and the transition to act as an impedance taper. A conical...
Graphene has become an outstanding material for revolutionary wireless applications in the microwave and terahertz/infrared frequency ranges. Due to its unique physical characteristics, a family of completely new devices can be developed by exploiting graphene's behaviour as High Impedance Surface (HIS) or highly-Reactive Impedance Surface (RIS). In this paper we theoretically investigate first a...
We report on a resonantly-coupled wireless power (RWPT) system for locomotion of a seat in an automobile environment. The seat moves transversely 28 cm, resulting in a time-varying geometry and coupling. In addition, the proximity of a metallic undercarriage creates the potential for interference and additional loss. We present a system that was able to achieve 80% efficiency over the entire 28 cm...
A methodology for improving efficiency of wireless power transfer (WPT) systems, derived from the concept of conjugate image impedances, is presented. For accuracy reasons, enhancement of the system efficiency through adjustment of its geometry parameters is based on full-wave electromagnetic (EM) simulation models. Fast WPT system design is realized by means of surrogate-based optimization exploiting...
This paper presents a generalization of the Oliner's method used to investigate the guided modes supported by a Sinusoidally-Modulated Surface Reactance (SM-SR). In its original paper, Oliner applied the procedure to the case of a scalar and impenetrable impedance sheet in free space; in this work, this approach has been extended to find the guided mode configurations (both leaky and surface waves)...
This paper presents a novel direction in leaky-wave phenomenon research: the generation of non-diffractive Bessel beams by leaky-wave modes. A radial waveguide loaded by a capacitive impedance sheet is used to support an azimuthally invariant leaky-wave mode whose normal electric-field component is a truncated, zeroth-order Bessel function. In particular, the generation of propagating Bessel beams...
Backward-wave oscillation is frequently a problem in TWT amplifiers that use the conventional circular helix slow-wave structure (SWS). Circular contra-wound helix SWS, proposed in the past to solve this problem, is hard to fabricate at high frequencies. In this paper, we propose a planar contra-wound planar helix SWS with potential for microfabrication. It is shown with the help of simulated dispersion...
This work addresses tunable matching networks fabricated on functional thick film layers of Barium-Strontium-Titanate (BST) for RF-power transistors. The deposition of BST layers is performed in a screen-printing process and the fabricated components are patterned by photolithography. Around 2.0 GHz, the insertion loss varies in a range between 0.7 dB and 1.1 dB depending on the tuning state and frequency,...
In this paper, a compact lumped element bandpass reconstruction filter for digital microwave power amplifier applications in the 800 MHz band is presented. The filter, based on the trisection topology, includes a cross coupling which produces a transmission zero for maximum selectivity. In contrast to common filter designs the input impedance characteristic is optimized broadband to values different...
An ultra-compact (2.5 cm2) rectenna design based on an innovative topology using a coplanar stripline connected to a crossed dipoles antenna array is reported here. Experimental results in the K-band show that a DC power up to 0.9 mW can be harvested on a 0.3 kΩ load by using the proposed compact rectenna for incident power density of 1413 µW/cm2. The targeted application for this rectenna is to power...
This paper presents theoretical analysis and experimental results for the optimum impedance matching condition of a rectenna in an EM energy harvester operating at low ambient power densities. The nonlinear behavior around the threshold voltage of the rectifier is analyzed. Closed-form equations for impedance matching and for predicting the dc output power are derived. A medium wave rectenna was designed...
This paper investigates the performance of wideband and high sensitivity RF power detectors. A resistive-matching, reactive-matching and distributed detectors are designed and measured. The distributed detector employs an artificial transmission-line structure. A six-stage distributed detector with a characteristic impedance of 205 Ω, is demonstrated to operate from very low frequencies to 3.2 GHz...
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