insertion losses
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2022 ◽  
Vol 12 (1) ◽  
pp. 492
Author(s):  
Suyeon Kim ◽  
Junhyung Jeong ◽  
Girdhari Chaudhary ◽  
Yongchae Jeong

This paper presents a design for a dual-band tunable phase shifter (PS) with independently controllable phase shifting between each operating frequency band. The proposed PS consists of a 3-dB hybrid coupler, in which the coupled and through ports terminate with the same two reflection loads. Each reflection load consists of a series of quarter-wavelength (λ/4) transmission lines, λ/4 shunt open stubs, and compensation elements at each operating frequency arm. In this design, a wide phase shifting range (PSR) is achievable at each operating frequency band (fL: lower frequency; fH: higher frequency) by compensating for the susceptance occurring at the co-operating frequency band caused by the λ/4 shunt open stub. The load of fL does not affect the load of fH and vice versa. The dual-band tunable PS was fabricated at fL = 1.88 GHz and fH = 2.44 GHz, and testing revealed that achieved a PSR of 114.1° with an in-band phase deviation (PD) of ± 8.43° at fL and a PSR of 114.0° ± 5.409° at fH over a 100 MHz bandwidth. In addition, the maximum insertion losses were smaller than 1.86 dB and 1.89 dB, while return losses were higher than 17.2 dB and 16.7 dB within each respective operating band.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jaouad Marzouk ◽  
Vanessa Avramovic ◽  
David Guérin ◽  
Steve Arscott

AbstractThe insertion losses of miniature gold/silicon-on-insulator (SOI) coplanar waveguides (CPW) are rendered low, stable, and light insensitive when covered with a thin film (95 nm) fluoropolymer deposited by a trifluoromethane (CHF3) plasma. Microwave characterization (0–50 GHz) of the CPWs indicates that the fluoropolymer stabilizes a hydrogen-passivated silicon surface between the CPW tracks. The hydrophobic nature of the fluoropolymer acts as a humidity barrier, meaning that the underlying intertrack silicon surfaces do not re-oxidize over time—something that is known to increase losses. In addition, the fluoropolymer thin film also renders the CPW insertion losses insensitive to illumination with white light (2400 lx)—something potentially advantageous when using optical microscopy observations during microwave measurements. Capacitance–voltage (CV) measurements of gold/fluoropolymer/silicon metal–insulator-semiconductor (MIS) capacitors indicate that the fluoropolymer is an electret—storing positive charge. The experimental results suggest that the stored positive charge in the fluoropolymer electret and charge trapping influence surface-associated losses in CPW—MIS device modelling supports this. Finally, and on a practical note, the thin fluoropolymer film is easily pierced by commercial microwave probes and does not adhere to them—facilitating the repeatable and reproducible characterization of microwave electronic circuitry passivated by thin fluoropolymer.


2021 ◽  
Vol 11 (23) ◽  
pp. 11342
Author(s):  
Francisco Pizarro ◽  
Pablo Stuardo ◽  
Ricardo Olivares ◽  
Eva Rajo-Iglesias

This article presents a parametric study using full-wave simulations about the potential use of cold plasma discharges to achieve frequency reconfiguration on a Sievenpiper mushroom metasurface. The study was done by inserting plasma tubes in between the patches of the mushroom structure, in three different positions with respect to the top of the metasurface, and varying the electronic density while keeping the plasma collision frequency. The obtained results show that it is possible to shift the stop-band generated by the metasurface around 25% towards lower frequencies for an electron density value inside the tubes of 1014 cm−3, when they are placed in between the top patches of the metasurface. Additional insertion losses are exhibited when operating near the plasma frequency.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Muhammad Ovais Akhter ◽  
Najam Muhammad Amin

This research proposed the design and calculations of ultra-low power (ULP) Doherty power amplifier (PA) using 65 nm CMOS technology. Both the main and the peaking amplifiers are designed and optimized using equivalent lumped parameters and power combiner models. The operation has been performed in RF-nMOS subthreshold or triode region to achieve ultra-low power (ULP) and to improve the linearity of the overall power amplifier (PA). The novel design consumes a DC power of 2.1 mW, power-added efficiency (PAE) of 29.8%, operating at 2.4 GHz band, and output referred 1 dB compression point at 4.1dBm. The simulation results show a very good capability of drive current, high gain, and very low input and output insertion losses.


Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1343
Author(s):  
Yevhen Yashchyshyn ◽  
Paweł Bajurko ◽  
Jakub Sobolewski ◽  
Pavlo Sai ◽  
Aleksandra Przewłoka ◽  
...  

RF switches, which use a combination of graphene and two-dimensional high-density electron gas (2DEG) in the AlGaN/GaN system, were proposed and studied in the frequency band from 10 MHz to 114.5 GHz. The switches were integrated into the coplanar waveguide, which allows them to be used in any system without the use of, e.g., bonding, flip-chip and other technologies and avoiding the matching problems. The on-state insertion losses for the designed switches were measured to range from 7.4 to 19.4 dB, depending on the frequency and switch design. Although, at frequencies above 70 GHz, the switches were less effective, the switching effect was still evident with an approximately 4 dB on–off ratio. The best switches exhibited rise and fall switching times of ~25 ns and ~17 ns, respectively. The use of such a switch can provide up to 20 MHz of bandwidth in time-modulated systems, which is an outstanding result for such systems. The proposed equivalent circuit describes well the switching characteristics and can be used to design switches with required parameters.


Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2507
Author(s):  
Gregory Beti Tanyi ◽  
Miao Sun ◽  
Christina Lim ◽  
Ranjith Rajasekharan Unnithan

We present the design of a plasmonic modulator based on hybrid orthogonal silver junctions using vanadium dioxide as the modulating material on a silicon-on-insulator. The modulator has an ultra-compact footprint of 1.8 μm × 1 μm with a 100 nm × 100 nm modulating section based on the hybrid orthogonal geometry. The modulator takes advantage of the large change in the refractive index of vanadium dioxide during its phase transition to achieve a high modulation depth of 46.89 dB/μm. The simulated device has potential applications in the development of next generation high frequency photonic modulators for optical communications which require nanometer scale footprints, large modulation depth and small insertion losses.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rupinder Kaur ◽  
Charanjit Singh ◽  
Rajbir Kaur

Abstract Hybrid wavelength-division-multiplexing (WDM) and free space optical (FSO) access networks are getting great attention due to numerous advantages. In this work, hybrid WDM-FSO system is demonstrated for 55 km at capacity of 5 × 10 Gbit/s using compressed spectrum return to zero (CSRZ) WDM-FSO in downstream and nonreturn to zero (NRZ) in upstream for demonstrating transmitter diversity which inturn decrease the interchannel interference. For the suppression of Rayleigh backscattering (RB) interferometric beat noise, bidirectional cyclic multiplexer is employed. Cyclic multiplexer provide λ 1 to λ 5 wavelengths for optical line terminal (OLT) to ONU transmission and λ 2 to λ 6 for ONU to OLT transmission. Insertion losses of each component are considered and in the end, power budget is also calculated. Results revealed that FSO length of 780–1050 m are obtained using various WDM-FSO downstream signals and their power budget, redundant budget, maximum distance, and insertion losses also calculated.


2021 ◽  
Author(s):  
Juliana Müller ◽  
Andrea Zazzi ◽  
Gayatri Vasudevan Rajeswari ◽  
Alvaro Moscoso-Mártir ◽  
Alireza Tabatabaei Mashayekh ◽  
...  

We present optimized hourglass-shaped resonator CROW filters showing an improved power consumption of up to 30% when compared with standard circular ring shapes. Metal and doped waveguide heaters are compared in terms of efficiency, crosstalk and insertion losses.


Author(s):  
Salah I. Yahya ◽  
Abbas Rezaei ◽  
Rafaa I. Yahya

In this work, we have used a novel adaptive neuro-fuzzy inference system (ANFIS) method to design and fabricate a high-performance microstrip diplexer. For developing the proposed ANFIS model, the hybrid learning method consisting of least square estimation and back-propagation (BP) techniques is utilized. To achieve a compact diplexer, a designing process written in MATLAB 7.4 software is introduced based on the proposed ANFIS model. The basic microstrip resonator used in this study is mathematically analyzed. The designed microstrip diplexer operates at 2.2[Formula: see text]GHz and 5.1[Formula: see text]GHz for wideband wireless applications. Compared to the previous works, it has the minimum insertion losses and the smallest area of 0.007 [Formula: see text] (72.2[Formula: see text]mm2). It has flat channels with very low group delays (GDs) and wide fractional bandwidths (FBWs). The GDs at its lower and upper channels are only 0.48[Formula: see text]ns and 0.76[Formula: see text]ns, respectively. Another advantage of this work is its suppressed harmonics up to 12.9[Formula: see text]GHz (5th harmonic). To design the proposed diplexer, an LC model of the presented resonator is introduced and analyzed. To verify the simulation results and the presented ANFIS method, we fabricated and measured the proposed diplexer. The results show that both simulations and measurements data are in good agreement, which give reliability to the proposed ANFIS method.


2021 ◽  
Vol 9 (1) ◽  
pp. 103-108
Author(s):  
Salah I. Yahya ◽  
Abbas Rezaei

A dual-band bandpass-bandpass microstrip diplexer with very small size and good performance is designed in this work. The proposed diplexer has a novel structure which is introduced for the first time in this paper. In comparison with the previously reported diplexers, it occupies the most compact size of 0.002 λg2 (226.7 mm2), fabricated on 0.787 mm dielectric substrate height. The resonance frequencies of the presented diplexer are located at 0.76 GHz and 1.79 GHz making it suitable for the global system for mobile communications (GSM) applications. It has a wide flat channels with two fractional bandwidths (FBWs) of 41.1% and 50%. Another feature of the proposed diplexer is its ability to suppress the harmonics. It can attenuate the 1st to 7th harmonics. Moreover, it has low insertion losses and low group delays at both channels while the isolation and return losses are acceptable. Finally, the proposed diplexer is fabricated and measured to verify the simulation results, where a good agreement between the simulation and measurement results is obtained.


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