scholarly journals Compact Wideband Antiparallel Diode Frequency Triplers Utilizing Planar Transitions

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Wahab Mohyuddin ◽  
Kang Wook Kim ◽  
Hyun Chul Choi
Keyword(s):  
Design Process ◽  
Impedance Matching ◽  
Wide Frequency Range ◽  
Harmonic Suppression ◽  
Type B ◽  
Output Impedance ◽  
Frequency Range ◽  
Conversion Loss ◽  
Input And Output ◽  
Even Harmonics

Two designs of frequency triplers, which use planar transitions as baluns and an antiparallel diode pair to achieve wide bandwidth, are presented. The ultrawideband transitions are utilized for input and output impedance matching of the frequency triplers. The design process and operation principles are described in this paper. The implemented frequency triplers exhibit flat response over wide frequency range of 3 to 9 GHz. The proposed Type A frequency tripler shows conversion loss of ~18 dB with above 30 dB even harmonics suppression. With Type B frequency tripler, conversion loss of ~17 dB and above 25 dB even harmonic suppression are achieved.

scholarly journals Flexible Broadband Metamaterial Perfect Absorber Based on Graphene-Conductive Inks

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 440
Author(s):  
Le Van Long ◽  
Nguyen Sy Khiem ◽  
Bui Son Tung ◽  
Nguyen Thanh Tung ◽  
Trinh Thi Giang ◽  
...  
Keyword(s):  
Impedance Matching ◽  
Optical Filters ◽  
Wide Frequency Range ◽  
Absorption Feature ◽  
Perfect Absorber ◽  
Frequency Range ◽  
Absorption Mechanism ◽  
Polarization Insensitive ◽  
Metamaterial Perfect Absorber ◽  
High Absorption

In this work, we proposed a flexible broadband metamaterial perfect absorber (FBMPA) by exploiting a pasted conductive-graphene ink on a polyimide substrate. For the flat FBMPA, an absorption over 90% was found to cover a wide frequency range (from 7.88 to 18.01 GHz). The high-absorption feature was polarization-insensitive and regarded as stable with respect to the oblique incidence up to 30 degrees of electromagnetic wave. The high absorption was maintained well even when the absorber was wrapped. That is, the FBMPA was attached to cylindrical surfaces (with the varying radius from 4 to 50 cm). For both flat and curved states, the absorption mechanism was explained by the perfect impedance matching and the dielectric loss of the proposed absorber. Our work provides the groundwork for the commercialization of future meta-devices such as sensors, optical filters/switchers, photodetectors, and energy converters.

scholarly journals Concurrent Quad-band Low Noise Amplifier (QB-LNA) using Multisection Impedance Transformer

2017 ◽  
Vol 7 (4) ◽  
pp. 2061
Author(s):  
Teguh Firmansyah ◽  
Anggoro Suryo Pramudyo ◽  
Siswo Wardoyo ◽  
Romi Wiryadinata ◽  
Alimuddin Alimuddin
Keyword(s):  
Figure Of Merit ◽  
Noise Figure ◽  
Impedance Matching ◽  
Low Noise ◽  
Low Noise Amplifier ◽  
Design System ◽  
Q Factor ◽  
Output Impedance ◽  
Input And Output ◽  
Noise Amplifier

<span>A quad-band low noise amplifier (QB-LNA) based on multisection impedance transformer designed and evaluated in this research. As a novelty, a multisection impedance transformer was used to produce QB-LNA. A multisection impedance transformer is used as input and output impedance matching because it has higher stability, large Q factor, and low noise than lumpedcomponent.The QB-LNA was designed on FR4 microstrip substrate with </span><span>e</span><span>r= 4.4, thickness h=0.8 mm, and tan </span><span>d</span><span>= 0.026. The proposed QB-LNA was designed and analyzed by Advanced Design System (ADS).The simulation has shown that QB-LNA achieves gain (S<sub>21</sub>) of 22.91 dB, 16.5 dB,  11.18 dB, and 7.25 dB at 0.92 GHz, 1.84 GHz, 2.61 GHz, and 3.54 GHz, respectively.The QB-LNA obtainreturn loss (S<sub>11</sub>) of -21.28 dB, -31.87 dB,  -28.08 dB, and -30.85 dB at 0.92 GHz, 1.84 GHz, 2.61 GHz, and 3.54 GHz, respectively. It also achieves a noise figure (nf) of 2.35 dB, 2.13 dB, 2.56 dB, and 3.55 dB at 0.92 GHz, 1.84 GHz, 2.61 GHz, and 3.54 GHz, respectively. This research also has shown that the figure of merit (FoM) of the proposed QB-LNA is higher than that of another multiband LNA.</span>

scholarly journals Evidence of Negative Capacitance and Capacitance Modulation by Light and Mechanical Stimuli in Pt/ZnO/Pt Schottky Junctions

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2253
Author(s):  
Raoul Joly ◽  
Stéphanie Girod ◽  
Noureddine Adjeroud ◽  
Patrick Grysan ◽  
Jérôme Polesel-Maris
Keyword(s):  
Impedance Matching ◽  
Mechanical Strain ◽  
Atomic Layer ◽  
Wide Frequency Range ◽  
Interface Trap ◽  
Negative Capacitance ◽  
Mechanical Stimuli ◽  
Trap States ◽  
Frequency Range ◽  
Schottky Junctions

We report on the evidence of negative capacitance values in a system consisting of metal-semiconductor-metal (MSM) structures, with Schottky junctions made of zinc oxide thin films deposited by Atomic Layer Deposition (ALD) on top of platinum interdigitated electrodes (IDE). The MSM structures were studied over a wide frequency range, between 20 Hz and 1 MHz. Light and mechanical strain applied to the device modulate positive or negative capacitance and conductance characteristics by tuning the flow of electrons involved in the conduction mechanisms. A complete study was carried out by measuring the capacitance and conductance characteristics under the influence of both dark and light conditions, over an extended range of applied bias voltage and frequency. An impact-loss process linked to the injection of hot electrons at the interface trap states of the metal-semiconductor junction is proposed to be at the origin of the apparition of the negative capacitance values. These negative values are preceded by a local increase of the capacitance associated with the accumulation of trapped electrons at the interface trap states. Thus, we propose a simple device where the capacitance values can be modulated over a wide frequency range via the action of light and strain, while using cleanroom-compatible materials for fabrication. These results open up new perspectives and applications for the miniaturization of highly sensitive and low power consumption environmental sensors, as well as for broadband impedance matching in radio frequency applications.

scholarly journals A New VCII Application: Sinusoidal Oscillators

2021 ◽  
Vol 11 (3) ◽  
pp. 30
Author(s):  
Vincenzo Stornelli ◽  
Gianluca Barile ◽  
Leonardo Pantoli ◽  
Massimo Scarsella ◽  
Giuseppe Ferri ◽  
...  
Keyword(s):  
Output Signal ◽  
Close Agreement ◽  
Second Generation ◽  
Current Mode ◽  
Wide Frequency Range ◽  
Output Impedance ◽  
Frequency Range ◽  
Positive Type ◽  
Sinusoidal Oscillators ◽  
Measurement Results

The aim of this paper is to prove that, through a canonic approach, sinusoidal oscillators based on second-generation voltage conveyor (VCII) can be implemented. The investigation demonstrates the feasibility of the design results in a pair of new canonic oscillators based on negative type VCII (VCII−). Interestingly, the same analysis shows that no canonic oscillator configuration can be achieved using positive type VCII (VCII+), since a single VCII+ does not present the correct port conditions to implement such a device. From this analysis, it comes about that, for 5-node networks, the two presented oscillator configurations are the only possible ones and make use of two resistors, two capacitors and a single VCII−. Notably, the produced sinusoidal output signal is easily available through the low output impedance Z port of VCII, removing the need for additional voltage buffer for practical use, which is one of the main limitations of the current mode (CM) approach. The presented theory is substantiated by both LTSpice simulations and measurement results using the commercially available AD844 from Analog Devices, the latter being in a close agreement with the theory. Moreover, low values of THD are given for a wide frequency range.

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