Search

Traditionally, phase shifters powered by power electronics are used in conjunction with energy storage devices to improve the load frequency control. Conventional phase shifters provide minimal inertia and offer a significant threat to power quality due to harmonics. This study suggests the type‐2 fuzzy based adaptively predictive controlled variable frequency transformer (F2‐APC‐VFT) as a phase shifter to work in coordination with superconducting magnetic energy storage (SMES) for improved load frequency control. To assess the effectiveness of coordinated control, a two‐area, four‐machine linked power system with F2‐APC‐VFT installed in succession with the connecting line near to area one and SMES in the other area is employed. A type‐2 fuzzy controller is used to tune the cost function weights of the adaptive predictive controller (APC). A simulation study is conducted in MATLAB to show the effectiveness of the suggested strategy. Tuning the cost function weights with a type‐2 fuzzy controller considerably impacts in minimising the frequency and tie‐power deviations. The effectiveness of the F2‐APC is verified by comparing its performance with that of an adaptive neuro fuzzy inference system (ANFIS) controller and constant weight‐based adaptive predictive controller (C‐APC). [ABSTRACT FROM AUTHOR]

Spacecraft commonly dissipate heat into space through radiation. In the current development of spacecraft radiators, two major challenges are encountered: effective dissipation of heat in high-temperature environments and the heat waste by the thermal control system. Thermoacoustic heat pumps have emerged as a promising solution, capable of increasing the dissipating temperature of the radiators and reusing the waste heat. This paper presents a novel work-recovery thermoacoustic heat pump (WRTAHP) that incorporates a displacer, which serves the function of phase shifter and acoustic power recovery. One-dimensional numerical simulations are conducted to investigate the influence of the regenerator, thermal buffer tube, heat exchangers, and displacer on the system performance. The results reveal that WRTAHP can raise the temperature of waste heat sources from 50 °C up to 120 °C and obtain 511 W heating capacity with an overall relative Carnot efficiency of 56.4%. Furthermore, with the utilization of the heat pump, the surface area of the radiator is reduced to 60% of its original size. This work demonstrates the potential of WRTAHP for space applications. [ABSTRACT FROM AUTHOR]

Recent developments in the standardization of magnetic field generators have been considered for optoelectronic industrial-scale applications. In this work, a strategy to incorporate all optical components that can be used to implement a broad range of functions for communications applications is presented. We propose a circuit design for a magneto-optic interferometric system based on building blocks and subcircuits consisting of an interferometer with magneto-optic phase shifters and a magnetic field generator. The paper shows the building blocks based on elementary 2 × 2 photonics coupling components. We demonstrate that such a design can be configured as a tunable system based on the phase shift experienced by the incoming signals from two input waveguides and their transitions. [ABSTRACT FROM AUTHOR]

Quasi-two-dimensional van der Waals (vdW) materials exhibiting room-temperature (RT) long-range ferromagnetic nature have emerged as a significant research field to explore fundamental condensed matter physics due to their intriguing physical properties. These vdW materials enable a futuristic platform for implementing novel spintronics devices. Here, we examined the spin dynamics of polycrystalline Fe5GeTe2 and Fe4.8Co0.2GeTe2 vdW materials using ferromagnetic resonance (FMR) spectroscopy. Vibrating Sample Magnetometer (VSM) study reveals that both materials have a soft ferromagnetic character at room temperature. From room temperature FMR measurements, the effective magnetization of Fe5GeTe2 and Fe4.8Co0.2GeTe2 derived ∼0.54 ± 0.056 and 0.50 ± 0.017 kOe, respectively. These results are consistent with reported VSM data. Fe5GeTe2 and Fe4.8Co0.2GeTe2 exhibit broad FMR linewidths of 0.697 ± 0.036 and 0.748 ± 0.056 kOe, respectively, which can be due to inhomogeneous line broadening. Besides its intrinsic contribution to linewidth, it is also affected by extrinsic Gilbert damping (αext). The value of αext is influenced by conflicting intra-band and inter-band electronic transitions, according to Modified Kambersky's theory. Furthermore, the effective Gilbert damping constant (α) obtained is 0.0513 ± 0.0046 for Fe5GeTe2 and 0.0526 ± 0.0031 for Fe4.8Co0.2GeTe2 at RT. Additionally, we developed microwave signal processing devices using these materials and evaluated their functionality both as a microwave band-reject filter and an adjustable phase shifter. The stop-band response was studied across the 5 to 25 GHz frequency range under an applied magnetic field as high as 7 kOe. For these flip-chip-based devices, attenuation is −5 dB/cm for the Fe5GeTe2-based filter and −3.2 dB/cm on sample Fe4.8Co0.2GeTe2 at 6.95 and 5.37 kOe, respectively. The same micro-strip filter was used as a tunable phase shifter in the off-resonance region. The optimal differential phase shift studied for Fe5GeTe2 and Fe4.8Co0.2GeTe2-based phase shifters in the high-frequency region (22 GHz for Fe5GeTe2 and 18 GHz for Fe4.8Co0.2GeTe2) is 23°/cm and 14°/cm, respectively, at high magnetic fields. These versatile devices find integration across a wide spectrum of applications, such as phased-array antennas, radar systems, and wireless communication systems, offering their benefits to diverse fields. [ABSTRACT FROM AUTHOR]

In this paper an all-optical half adder has been designed on a 2D photonic crystal slab having air holes in a hexagonal lattice pattern. The working principal of the device is based on beam interference. Multi-mode interference based Pi phase shifter been used in this design. Neither any nonlinear materials nor any extra bias signal has been incorporated in the structure. Plain wave expansion and Finite Difference Time Domain methods have been used for analyzing the band diagram of the structure and performance of the proposed device respectively. The SUM port provides 60%, 67%, and 1% transmittance whereas the CARRY port provides 4%, 1%, and 90% transmission for {0,1}, {1,0}, and {1,1} logic combinations respectively. Minimum contrast ratio has been obtained as 18 dB in SUM port and 12.5 dB in CARRY port. Therefore, it is expected that the proposed all-optical adder would be a potential candidate for future generation photonic integrated circuits. [ABSTRACT FROM AUTHOR]

A microwave photonic frequency-doubling phase shifter with a broad bandwidth and large tuning range is proposed in this paper. Frequency doubling and phase shifting are realized by processing the input microwave signal in the optical domain at a dual-drive dual-parallel Mach–Zehnder modulator (DD-DPMZM) and a dual-parallel Mach–Zehnder modulator (DPMZM). The input signal is split into two branches through a 90-degree hybrid splitter. One signal is sent to the DD-DPMZM to achieve a phase-shifted carrier-suppressed up-sideband by tuning the bias voltage, and the other is sent to the DPMZM to realize a carrier-suppressed down-sideband. By beating the phase-shifted up-sideband and the down-sideband at a photodetector (PD), the input signal is frequency doubled and phase shifted. The proposed frequency-doubling phase shifter is simulated. The results show that the frequency-doubled signal has a phase-tuning range from 0 to 360 degrees. In addition, the influence of the amplitude and phase unbalance of the 90-degree hybrid splitter on the magnitude variation and phase deviation of the frequency-doubling phase shifter is studied. [ABSTRACT FROM AUTHOR]

This work introduces a novel architecture for implementing a parallel coherent photonic digital-to-analog converter (PDAC), designed to transform parallel digital electrical signals into corresponding analog optical output, convertible to analog electrical signals using photodiodes. The proposed architecture incorporates microring resonator-based modulators (MRMs), phase shifters, and symmetric multimode interference couplers. Efficient modulation is achieved by MRMs utilizing carrier depletion-induced refractive index changes, while metal heaters facilitate tuning of the ring resonator resonance wavelength. The proposed architecture is scalable to higher bit resolutions and exhibits a dynamic range limited by MRM's sensitivity to applied bias and noise levels. Experimental results of the fabricated chip in the silicon-on-insulator (SOI) platform showcase the successful realization of a 4 GSample/sec conversion rate in a 2-bit resolution operation, along with a stationary conversion of four parallel DC digital signals into 16 analog intensity levels in a 4-bit PDAC configuration. The study encompasses a proof-of-concept experimental demonstration of 8 Gbps data conversion, along with a 50 Gbps data conversion rate using the optimized design in the simulation, affirming the accuracy and quality of the PDAC architecture. These findings contribute to the advancement of PDAC technology, providing insights into performance characteristics, limitations, and potential applications. [ABSTRACT FROM AUTHOR]

This work serves as the first simulation investigation to tackle the liquid crystal (LC)-filled coaxially structured continuously variable phase shifter at 60 GHz, wherein the LCs act as single tunable dielectrics fully occupying the millimeter-wave (mmW) power transmitted (i.e., free of leakage or interference). Impedance and effective dielectric constant computations are settled, followed by the quantification of the interplay between the dielectric thickness and the dielectric constant (Dk) for a controlled 50 Ω impedance. Geometry's aspect ratio (AR) effects are exploited for the coaxially accommodating topology filled with mmW-tailored LCs with an operatable Dk range of 2.754 (isotropic state) to 3.3 (saturated bias state). In addition to the proposed structure's noise-free advantages, a novel figure of merit (FoM) enhancement method based on Dk-selection-based impedance matching is proposed. The optimum FoM design by simulation exhibits a 0–180.19° continuously variable phase shift with a maximum insertion loss of 1.75871 dB, i.e., a simulated FoM of 102.46°/dB when the LC-filled coaxial geometry is 50 Ω and matched with the Dk of 2.8, corresponding to the dielectric thickness of 0.34876 mm and line length of 15.92 mm. The envisioned device fabrication and assembly processes are free of the conventional polyimide alignment agent and the related thermal and electrical concerns. Significant cost reduction and yield improvement can hence be envisaged. The topology can also serve as a test structure for broadband characterizations of LC materials and new electro-optical effects. [ABSTRACT FROM AUTHOR]

This document is an editorial for a special issue of the journal Micromachines on recent advances in microwave components and devices. The editorial highlights the importance of microwave engineering in communication, sensing, and monitoring systems, and discusses the current and emerging advancements in the field. The articles in the special issue cover various aspects of microwave engineering, including RF front-ends, filters, phase shifters, power amplifiers, antennas, microwave sensors, and programmable metasurfaces. The editorial aims to provide readers with an overview of the state-of-the-art developments in microwave technology and inspire future research in the field. [Extracted from the article]

In this article, a tunable RF sensor is presented for the measurement of dielectric materials (liquids and solids) based on a metamaterial resonator. The proposed novel configuration sensor has a microstrip line-loaded metamaterial resonator with tunable characteristics by utilizing a single varactor diode in the series of the resonator. CST Microwave studio is employed for 3D simulations of the tunable sensor, and the desired performance is attained by optimizing various structural parameters to enhance the transmission coefficient ( S 21 magnitude) notch depth performance. The proposed RF sensor can be tuned in L and S-bands using the varactor diode biasing voltage range of 0–20 V. To validate the performance of the sensor, the proposed design has been simulated, fabricated, and tested for the dielectric characterization of different solid and liquid materials. Material testing is performed in the bandwidth of 1354 MHz by incorporating a single metamaterial resonator-based sensor. Agilent's Network Analyzer is used for measuring the S-parameters of the proposed sensor topology under loaded and unloaded conditions. Simulated and measured S-parameter results correspond substantially in the 1.79 to 3.15 GHz frequency band during the testing of the fabricated sensor. This novel tunable resonator design has various applications in modulators, phase shifters, and filters as well as in biosensors for liquid materials. [ABSTRACT FROM AUTHOR]

In the paper, a wideband tunable 4 × 4 Nolen matrix is proposed. By using the presented topology of the Nolen matrix, tunable output port phase differences can be realized by inserting one type of tunable phase shifters (T-PS). Besides, the in-band phase deviation error is minimized by adding compensation phase shifters (C-PSs) to the output ports of the Nolen matrix. Analytical design methods based on signal flow graphs and complex exponential signal are given to obtain the rigorous relationships of the coupling and phase shifts in the Nolen matrix. Besides, a detailed method for output ports phase slope compensation is provided. For validation, a prototype centered at 5.8 GHz is designed and fabricated. Measurement results agree well with the simulated ones. By using only one voltage to control the phase shifts of the T-PS in a 90° range for each input excitation of the Nolen matrix, a full 360° range of the progressive phase difference is realized by switching four input ports. The measured fractional bandwidth under 10 dB return loss and isolation is larger than 24.5% with the in − band ± 1.5 dB amplitude imbalance and ±15° phase deviation error for ports 1-4 excitations. Besides, for a more strict criterion of ±1 dB amplitude imbalance and 10° phase deviation error, the measured bandwidths are larger than 15% for all port excitations. [ABSTRACT FROM AUTHOR]

A variety of topological Hamiltonians have been demonstrated in photonic platforms, leading to fundamental discoveries and enhanced robustness in applications such as lasing, sensing, and quantum technologies. To date, each topological photonic platform implements a specific type of Hamiltonian with inexistent or limited reconfigurability. Here, we propose and demonstrate different topological models by using the same reprogrammable integrated photonics platform, consisting of a hexagonal mesh of silicon Mach-Zehnder interferometers with phase shifters. We specifically demonstrate a one-dimensional Su-Schrieffer-Heeger Hamiltonian supporting a localized topological edge mode and a higher-order topological insulator based on a two-dimensional breathing Kagome Hamiltonian with three corner states. These results highlight a nearly universal platform for topological models that may fast-track research progress toward applications of topological photonics and other coupled systems. Topological photonics could impact the scalability of integrated photonics, but it has shown limited reconfigurability to date. Here, the authors demonstrate reprogrammable integrated photonics as a nearly universal platform for topological models. [ABSTRACT FROM AUTHOR]

Recently, interest in programmable photonics integrated circuits has grown as a potential hardware framework for deep neural networks, quantum computing, and field programmable arrays (FPGAs). However, these circuits are constrained by the limited tuning speed and large power consumption of the phase shifters used. In this paper, we introduce the memresonator, a metal-oxide memristor heterogeneously integrated with a microring resonator, as a non-volatile silicon photonic phase shifter. These devices are capable of retention times of 12 hours, switching voltages lower than 5 V, and an endurance of 1000 switching cycles. Also, these memresonators have been switched using 300 ps long voltage pulses with a record low switching energy of 0.15 pJ. Furthermore, these memresonators are fabricated on a heterogeneous III-V-on-Si platform capable of integrating a rich family of active and passive optoelectronic devices directly on-chip to enable in-memory photonic computing and further advance the scalability of integrated photonic processors. Photonic integrated circuits have grown as potential hardware for neural networks and quantum computing, yet the tuning speed and large power consumption limited the application. Here, authors introduce the memresonator, a memristor heterogeneously integrated with a microring resonator, as a non-volatile silicon photonic phase shifter to address these limitations. [ABSTRACT FROM AUTHOR]

This article presents a 4-way 2-D butler matrix (BM)-based beamforming network (BFN) using a multilayer substrate broadside coupled stripline (BCS). To achieve the characteristics of a compact, wide-bandwidth, high-gain phased array, a BCS coupler is implemented using the Megtron 6 substrate. The compact 2-D BFN is formed by combining planarly two horizontal BCS couplers and two vertical BCS couplers. The BFN is proposed without a crossover and without a phase shifter, generating phase responses of ±90° in the x- and y-directions, respectively. The proposed BFN exhibits a wide operating band of 66.7% (3–7 GHz) and a compact physical area of just 0.25 λ0 × 0.25 λ0 × 0.04 λ0. The planar 2-D BFN is easily integrated with the patch antenna radiation elements to construct a 2-D multibeam array antenna that generates four fixed beams, one in each quadrant, at an elevation angle of 30° from the broadside to the array axis when the element separation is 0.6 λ0. The physical area of the 2-D multibeam array antenna is just 0.8 λ0 × 0.8 λ0 × 0.04 λ0. The prototypes of the BCS coupler, the 2-D BFN, and the 2-D multibeam array antenna were fabricated and measured. The measured and simulated results were in good agreement. A gain of 9.1 to 9.9 dBi was measured. [ABSTRACT FROM AUTHOR]

Heterogeneity investigation at the single-cell level reveals morphological and phenotypic characteristics in cell populations. In clinical research, heterogeneity has important implications in the correct detection and interpretation of prognostic markers and in the analysis of patient-derived material. Among single-cell analysis, imaging flow cytometry allows combining information retrieved by single cell images with the throughput of fluidic platforms. Nevertheless, these techniques might fail in a comprehensive heterogeneity evaluation because of limited image resolution and bidimensional analysis. Light sheet fluorescence microscopy opened new ways to study in 3D the complexity of cellular functionality in samples ranging from single-cells to micro-tissues, with remarkably fast acquisition and low photo-toxicity. In addition, structured illumination microscopy has been applied to single-cell studies enhancing the resolution of imaging beyond the conventional diffraction limit. The combination of these techniques in a microfluidic environment, which permits automatic sample delivery and translation, would allow exhaustive investigation of cellular heterogeneity with high throughput image acquisition at high resolution. Here we propose an integrated optofluidic platform capable of performing structured light sheet imaging flow cytometry (SLS-IFC). The system encompasses a multicolor directional coupler equipped with a thermo-optic phase shifter, cylindrical lenses and a microfluidic network to generate and shift a patterned light sheet within a microchannel. The absence of moving parts allows a stable alignment and an automated fluorescence signal acquisition during the sample flow. The platform enables 3D imaging of an entire cell in about 1 s with a resolution enhancement capable of revealing sub-cellular features and sub-diffraction limit details. [ABSTRACT FROM AUTHOR]

Nonreciprocal devices, including optical isolators, phase shifters, and amplifiers, are pivotal for advanced optical systems. However, exploiting natural materials is challenging due to their weak magneto‐optical (MO) effects, requiring substantial thickness to construct effective optical devices. In this study, it is demonstrated that subwavelength metasurfaces supporting bound states in the continuum (BICs) and made of conventional ferrimagnetic material can exhibit strong nonreciprocity in the Faraday configuration and near‐unity magnetic circular dichroism (MCD). These metasurfaces enhance the MO effect by 3–4 orders of magnitude compared to a continuous film of the same material. This significant enhancement is achieved by leveraging Huygens' condition in the metasurface whose structural units support paired electric and magnetic dipole resonances. The multi‐mode temporal coupled mode theory (CMT) is developed for the observed enhancement of the MO effect, and the findings with the full‐wave simulations are confirmed. [ABSTRACT FROM AUTHOR]

In this paper, we propose a microwave photonic phase shifter (MPPS) without optical filtering to generate a frequency octupling microwave photonic (MWP) signal with 360º phase-shifting based on two cascaded Mach–Zehnder modulators (MZMs). Theoretical analysis is given to realize the high-quality frequency octupling MPPS by eliminating the undesired optical carrier and sidebands using an optical coupler (OC). Simulations show that the generated MMW signal has an electrical spurious suppression ratio (ESSR) higher than 33 dB. The impact of the non-ideal modulation index, extinction ratio, and phase drift is discussed and analyzed. Furthermore, the influence of different center frequencies, power, and linewidths of the laser is also analyzed. [ABSTRACT FROM AUTHOR]

• A two-stage gas-coupled Stirling/pulse tube refrigerator with a second-stage active phase shifter is developed. • The effect of the active phase shifter on the acoustic power and phase distribution is investigated. • The regulation of the inter-stage refrigeration capacity shift by the active phase shifter phase and amplitude is analyzed. • Experiment results are carried out to verify the theoretical and simulated analyses. The Stirling/pulse tube cryocooler (SPC) is one of the most promising cryocoolers for space applications due to its advantages like high efficiency and long lifetime. The second pulse tube stage is coaxial pneumatically coupled in series with the first Stirling stage. The SPC possesses a distinctive capability to dynamically adjust the inter-stage refrigeration capacity by actively controlling the Stirling displacer in the first stage. This enables the SPC to effectively cater to varying heat loads over time. Nevertheless, the investigation into the regulation mechanism of the second-stage phase shifter on inter-stage refrigeration capacity shift is hindered by the presence of the second-stage passive phase shifter. This manuscript proposes an SPC with a second-stage active phase shifter (APS), which can actively control the phase difference between the pressure wave and mass flow at the second-stage hot end of the pulse tube in real time. The effect of the APS phase and amplitude on the inter-stage refrigeration capacity shift is analyzed using the theoretical and numerical model proven by the experiment. The first experimentally reported SPC with a second-stage APS demonstrates a refrigeration capacity of 0.22 W at 20 K plus 3.11 W at 70 K, requiring a compressor electrical power of 220 W. The SPC achieves a no-load minimum temperature of 13.5 K. [ABSTRACT FROM AUTHOR]

This article deals with the operational behavior of barium hexaferrite (BHF) disc when incorporated in microwave substrates for wireless applications. A microstrip line printed on a Rogers substrate (35 mm × 35 mm × 1.6 mm) has been used in the design to observe the effect of BHF material. A BHF circular‐shaped disc of radius 4.5 mm and thickness 1 mm is inserted in the middle of the microstrip line. The ferrite is biased using miniature lightweight neodymium magnets stacked one over the other to obtain desired magnetic field strength. The proposed microstrip line inserted with a BHF disc exhibits wide band isolation properties in the K‐band (15–21 GHz) with an average isolation of 20 dB and peak isolation of 51 dB centered at 18.5 GHz. It is observed that the same circuit is behaving as a phase shifter showing a 45° ± 3° phase shift in the band ranging from 12 to 14 GHz. The proposed compact microstrip‐line circuit can be used as both ferrite phase shifter and isolator in consecutive bands (Ku‐ and K‐bands) with ease of integration and biasing. [ABSTRACT FROM AUTHOR]

This study presents the design and fabrication of a novel direct current (DC)/capacitive radio frequency (RF) Micro‐Electro‐Mechanical Systems (MEMS) switch in the ultrabroadband range from DC to 80 GHz. This proposed RF MEMS switch consists of two arms, with one arm providing a DC loading state (S1 ${S}_{1}$), whereas the second arm provides a capacitive loading state (S2 ${S}_{2}$) to the ground when pull‐in voltage is applied. Insertion loss less than 1.85 dB and return loss better than 10 dB are achieved in the OFF state (S0 ${S}_{0}$) from DC to 80 GHz (no pull‐in voltage is applied). Due to the novel design topology, this switch can act as a DC‐only switch (0–17 GHz) that provides isolation better than 25 dB during the S1 ${S}_{1}$ state. A capacitive‐only switch (48–80 GHz) provides isolation better than 17 dB. This proposed structure can act as either DC(S1) or a capacitive (S2 ${S}_{2}$) switch (17–48 GHz) and provides isolation better than 10 dB in either state. This proposed switch finds its best application in reconfigurable circuits like phase shifters due to switching between DC and capacitive loading during the On state from 17 to 48 GHz. The proposed switch's measured pull‐in and lift‐off voltages are 3.5 and 2.85 V, respectively. [ABSTRACT FROM AUTHOR]

In this study, the concept of the nonlinear phase shifter is proposed to provide a new idea for the hardware architecture of sensing reconfigurable intelligent surfaces (RISs). First, the equivalent circuit of the proposed phase shifter is given to provide theoretical guidance for the design. Then, the nonlinearity analysis of the nonlinear phase shifter is presented. Finally, two simplified sensing RIS elements operating at 4 GHz was fabricated and measured to validate the design. The measured scanning range was from 16° to −18° with the input power increasing from 5 to 23 dBm. The nonlinear phase shifter shows great application potential in sensing RISs. [ABSTRACT FROM AUTHOR]

A scheme of generating millimeter‐wave signals with 16 times frequency using a cascaded Mach–Zehnder modulator (MZM) is proposed. Optical delay lines (ODLs) are used to place between cascaded MZMs, two MZMs work at the maximum transmission point. By controlling the modulation index of the MZM and the delay of the ODL, 0‐order, ±8 $\pm 8$‐order, and ±12 $\pm 12$‐order sidebands can be generated. The optical phase shifter and attenuator are adjusted to eliminate the 0‐order sideband, and the photodetector output generates a frequency 16‐tupling millimeter wave (MMW). In the simulation platform, a 160‐GHz MMW signal can be obtained by taking a 10‐GHz radio frequency signal as the driving signal of two MZMs. The optical sideband suppression ratio is 29.92 dB, and the radio frequency sideband suppression ratio is 24.89 dB. Further, the effect of system performance on optical devices under nonideal conditions is also discussed. [ABSTRACT FROM AUTHOR]

In this study, a true three‐dimensional dot‐shaped beamforming, in which the transmitted energy in a spatial region (azimuth, elevation, and range) is focused is performed with the nonuniform time‐modulated concentric circular frequency diverse array (NUTM‐CCFDA). The CCFDA structure with a radially outward increasing frequency offset between the rings has structural symmetry that provides the advantage of full scanning in the azimuth plane without any significant change in beam shape. Moreover, the NUTM, where the antenna elements are simply excited with a different modulation frequency in each ring, uses the in‐phase/quadrature channel modulator to realize a single sideband. The proposed NUTM‐CCFDA structure exhibits efficient beam scanning with the switch time‐on instant without using variable phase shifters to steer the dot‐shaped beam. Thus, NUTM‐CCFDA not only realizes a true dot‐shaped beam with better angle resolution on the first harmonic components but also has a simpler configuration than the conventional frequency diverse arrays with sophisticated variable frequency/phase shifters. [ABSTRACT FROM AUTHOR]

Detuning errors limit the accuracy of phase extraction in phase-shifting interferometry (PSI). To improve this accuracy, the systems to control the phase shifter dispositive must be highly accurate, involving high technology, exhaustive calibration, high cost, and constant maintenance. This manuscript presents a method for improving the accuracy of the phase step generated at the Fourier plane by rotating and displacing the grating in a double-aperture common-path interferometer. It is demonstrated that both the detuning errors and the phase extraction uncertainty decrease with the grating rotation angle. The experimental implementation is very simple, as it does not require any sophisticated mechanical system to improve the accuracy, no exhaustive calibration, and no additional mechanical and optical dispositive. With the present approach, the PSI method could be achieved very simply and with high accuracy by using a low-accuracy actuator. The theoretical model and experimental results are presented to demonstrate the present proposal. [ABSTRACT FROM AUTHOR]

A reconfigurable inductorless negative‐refractive‐index transmission‐line (NRI‐TL) metamaterial phase shifter for sub‐6 GHz 5G antenna applications is proposed. The design consists of a microstrip transmission line loaded both in series and in parallel with varactor diodes to provide continuous tuning of the phase of the transmitted signal by varying the bias voltage applied to the varactors, without the need for variable inductor components. The total measured differential phase shift is 190° at 3.2 GHz, with a measured insertion loss of 1.5–2.7 dB in the frequency range of 3.2–3.6 GHz, when the biasing voltage of the varactors is varied between 0 and 7 V. The total size of the microstrip NRI‐TL phase shifter is 19.4 mm × 24 mm. The proposed reconfigurable phase shifter has been incorporated into the feeding network of a two‐element antenna array to demonstrate its use in beam‐steering applications. The measured results for the reconfigurable array show good impedance matching between 3 and 3.35 GHz for all biasing values, allowing continuous beam steering over a scanning range of 60°. [ABSTRACT FROM AUTHOR]

This paper presents a phased array system (PAS) with built-in calibration to reduce cost and improve the accuracy for vehicle-to-everything (V2X) communications. Unlike other high-complexity and high-cost calibration methods, our proposed built-in calibration achieves a lower cost and low complexity by detecting only the magnitude. Conventional built-in calibration uses a mixer, thus causing high power consumption and high cost. However, our proposed built-in calibration method searches for the minimum of the vector-sum point from the signal by sampled lines on-board, resulting in a higher accuracy. The vector-sum point goes to a minimum when the phase and magnitude are in balance. Therefore, the phase and magnitude imbalance can be easily monitored by controlling phase shifters and attenuators in PAS. To verify our proposed built-in calibration in PAS, a T/Rx with four RF-chains and sampled lines was fabricated at 5.8 GHz. Its performance was then demonstrated through simulated and measured results. Moreover, a communication performance evaluation using an actual vehicle was performed both before and after calibration. As a result, we found that a signal without distortion was transmitted after calibration. [ABSTRACT FROM AUTHOR]

Wideband phased arrays for Electronic Warfare (EW) applications utilize narrowband phase shifters in a switched configuration to cover a multi-octave bandwidth in split bands. Wideband True Time Delay (TTD) line circuits are the best candidates to replace narrowband phase shifters in such systems, covering the complete operating bandwidth in a single step. The Transmit Receive Module (TRM) is a critical component of any phased array system. A novel design of a TTD line-based Octal Transmit Receive Module (OTRM) for a 32-element EW phased array over a frequency range of 1-6 GHz is presented in this paper. The OTRM is designed on a single multi-layer PCB by integrating eight transmit-receive (TR) channels, associated controllers, and power conditioning circuitry in a compact size and weight of 800 grams. The paper addresses challenges associated in the design of TR channels to fit within the inter-element spacing of 14 mm and to achieve isolation of = 40 dB between channels. The designed OTRM tunes time delay up to 508 ps maximum with a step of 2 ps by using a single TTD line circuit for ±45 scan coverage. The OTRM has demonstrated its potential capability for the use in wideband Radar, EW, and Communication system applications. Efficient thermal management of the OTRM is achieved by introducing Copper coins below the final power amplifiers and a liquid cold plate to dissipate a heat load of 32 watts per TR channel. The proposed OTRM delivers transmit power of 8 watts (CW), receive gain of 25 dB, and a noise figure of 6 dB per TR channel with an overall efficiency of 19% (min) over a 5 GHz bandwidth. RF path analysis of the TR channel in transmit and receive paths is carried out using the Systemvue software tool. To verify the design of the OTRM over different time delay and attenuator states, measurements are conducted using a Vector Network Analyzer (VNA). [ABSTRACT FROM AUTHOR]

The purpose of this paper is to study the RF/microwave constant phase shift (CPS) designed as an integrated circuit (IC) in 130-nm Bi-CMOS technology. The CPS understudy is constituted by a bandpass (BP) negative group delay (NGD) passive cell combined in cascade with a positive group delay (PGD) circuit. The CPS real circuit is represented by a CLC-network associated in cascade with a BP-NGD passive cell. The CPS characterization is based on the S-parameter modelling. The CPS is analytically modeled by the frequency independent transmission phase modelling by the mathematical relation φ(f) = a * exp(-j * φ0) = constant around working frequency [fn - Δf/2, fn + Δf/2] by denoting center frequency fn and frequency band Δf. The analytical principle of the constant PS is explored by means of the RLC-network based NGD cell. The design formula of the NGD and CLC passive circuit parameters in function of desired operation frequency is established. The validity of the developed theory is verified with a proof-of-concept (POC). A CPS miniature IC having physical size 1.15mm × 0.7mm is designed and implemented as POCin 130-nm Bi-CMOS technology. The ADS R® and layout versus schematic of Cadence R® simulation results from 130-nm Bi-CMOS CPS POC confirms the theoretical investigation feasibility. The simulated results of the obtained CPS IC POC layout show φ0 = -67◦+/-1◦ phase shift around fn = 0.85 GHz within the frequency band delimited by f1 = 0.73 GHz to f2 = 0.984 GHz or Δf = f2 - f1 = 254 GHz. The CPS robustness designed in 130-nm Bi-CMOS IC technology is stated by Monte Carlo statistical analysis from 1000 trials with respect to the component geometrical parameters. It was reported that the phase shift and insertion loss flatness's of the CPS IC is guaranteed lower than 5% in Δf/fn = 30% relative frequency band around fn. [ABSTRACT FROM AUTHOR]

Digital filtration is widely used today in many application fields, and with the increased use of low-cost embedded processors, it can be applied to vast areas. A drawback of digital filtration algorithms is the introduction of phase angle shifts in the filtered signals, thereby creating undesirable characteristics in many application fields. In this work, low-pass filters of finite impulse response and infinite impulse response types are designed with an innovative buffering scheme to delay a digitally low-passed signal by an angle ranging from 0° to 180° for real-time signals. The application of the filtration and buffering scheme on a cost-effective embedded processor with limited signal processing capabilities opens the horizons for its applicability in many signal processing fields. In assessing its practicality, the generated filtered output signal is correlated with the original signal (a low-passed version), revealing correlation values reaching 0.99 in certain instances. The novelty of the proposed approach enables its application to a broad-spectrum area of digital signal filtration. [ABSTRACT FROM AUTHOR]

A novel ultra-compact dual-band reconfigurable microstrip phase shifter designed by using a dual-composite right/left handed D-CRLH technique of metamaterial is introduced. The paper proposes detailed studies between the simulation and the fabricated prototype results. Moreover, the study of the proposed phase shifter explains a shifting range from 0° till 360° by submitting four mounted surface switches in different spots of the fingers. Switches have fixed states shifting to provide the controlling of the requested range. The switches were chosen to be from PIN Diode as it has many compatible characteristics which are explained in the proposed paper. The reconfigurable phase shifter designed with high quality factors and low insertion loss 0.25 and 0.2 at 5.7 GHz and 7.5 GHz respectively with a very compact size area 8 × 11. The proposed shifter supports the application of wide band usage especially for network access point, Wi-Fi, WiMAX network, and wireless LAN connections in addition to the application of point to point microwave radio links and X-band of satellite & space communications. [ABSTRACT FROM AUTHOR]

Due to the high-power consumption and complexity of fully digital baseband precoding, its implementation in massive millimeter-wave multiple-input multiple-output (MIMO) systems is not cost-efficient and practical; for this reason, hybrid precoding has attracted a lot of attention in recent years. Most hybrid precoding techniques concentrate on the fully-connected structure, although they require lots of phase shifters, which is high energy-consuming. On the contrary, the partially-connected structure has low power consumption, nevertheless, suffers from a severe decrease in spectral efficiency (SE). To enhance SE, this paper proposed a dynamic hybrid precoding structure where a switch network is able to provide dynamic connections from phase shifters to radio frequency (RF) chains. To determine the digital precoder and the states of switch, a novel alternating minimization algorithm is proposed, which leverages closedform solutions at each iteration to efficiently converge to an optimal solution. Furthermore, the phase shifter matrix is optimized through an iterative solution. The simulation results show that in terms of SE, the proposed algorithm with a dynamic structure achieves higher performance than the partial structure. Also, since the proposed structure reduces the number of phase shifters, it can guarantee better energy efficiency (EE) than the fully connected structure. [ABSTRACT FROM AUTHOR]

Massive MIMO embraces digital beamforming techniques to direct power to the intended users. However, digital beamforming is power-consuming as each antenna has a dedicated RF chain. To address this issue, a hybrid beamforming architecture was proposed, where analog beamforming is combined with a low dimension digital beamforming. Consequently, the number of RF chains was significantly reduced. The conventional hybrid beamforming architecture deploys phase shifters in analog beamforming, which consumes large power as the number of antennas increases. This work proposes a phase interpolator-based analog beamforming to reduce the number of phase shifters in the fully connected hybrid beamforming architecture. Additionally, we have formulated an optimization problem to search for the best analog and digital precoding in order to maximize spectral efficiency. Solving this problem, we have proposed a tabu search (TS) based algorithm, which uses a genetic algorithm crossover feature to search for the new neighbor. Simulation results show that the proposed method achieves high spectral efficiency and energy efficiency. Specificall, when SNR = 0 dB, the proposed method achieves 95% spectral efficiency of an optimal solution, and achieves 20% higher energy efficiency than conventional method. Furthermore, the proposed method achieves high spectral efficiency with low computational complexity, in comparison to conventional methods. [ABSTRACT FROM AUTHOR]

New configurations of 2-D phased arrays are proposed in this paper for reducing the number of phase shifters. This design methodology is based on the use of a novel coherently radiating periodic structures (CORPSs) block for 2-D phased arrays. Two new antenna systems for 2-D phased arrays are studied and analyzed utilizing the CORPSs blocks of four inputs and nine outputs. These CORPSs feeding blocks are applied in a smart way to feed the planar antenna arrays by generating the required phase plane and reducing the number of control ports. Interesting results are provided based on the experimental measurements and full-wave simulations. These results illustrate a great reduction of the active devices (phase shifters), providing a good design compromise in terms of the scanning range and side lobe level performance. Furthermore, the provided results illustrate a maximum reduction capability in the number of phase shifters of 81%, considering a scanning range of ±30° in azimuth and ±30° in elevation. A raised cosine distribution is applied to reach side lobe levels of −19 dB for ±18° and −17 dB for ±30° in elevation. These benefits could be of interest to designers of phased antenna systems.

Controlling magnetic damping lies at the heart of spintronic applications. In particular, manipulating the radiative damping of magnons is important for the emerging dissipative magnon–photon coupling and, therefore, opens up possibilities for advanced hybrid magnonic devices, nonreciprocal transmission, and topological information processing. The materials or structures that produce magnon modes can be further enriched with an artificial magnon mode produced in a complementary electric inductive–capacitive (CELC) resonator due to its flexible tunability, miniaturized size, and easy integration. Here, we explore the radiative linewidth broadening and frequency shifts of a CELC resonator in an on-chip coplanar waveguide in a self-interfering configuration. The radiative dynamics depends on the magnetic component of the local density of photon states, as well as the intensity, polarization, and boundary conditions. In particular, a voltage-controlled phase shifter was integrated to demonstrate voltage-controlled radiative damping. Adopting both the CELC resonator and its complementary structure may be an effective tool for obtaining the spatial distribution of the electric and magnetic components of microwaves. Our work is a general approach to manipulating the radiative damping of magnetic resonance, which has the potential for on-chip functional devices based on dissipative magnon–photon interactions. [ABSTRACT FROM AUTHOR]

Abstract This work presents a comparative analysis and design procedure of a converter based on an LLC resonant inverter used for induction heating applications depending on the transistor technology used and the selected operating frequency. A major objective of the work is to determinate the inverter design requirements leading to the optimal sizing of the components, improving its operation and minimizing power losses. Additionally, it proposes a design to obtain a great insensitivity of the inverter operation against large variations of load impedance. This article analyzes the operation of the inverter where the power regulation is carried out by phase‐shift (PS) modulation. Simple rules are formulated for the design of the resonant circuit components. The design has been verified testing a 25‐kW inverter in an industrial application of induction hardening operating at 500 kHz. Inverter efficiency is around 98.5% when using Silicon Carbide (SiC) MOSFETs.

Abstract In this study, a direct synthesis approach is proposed to extract the coupling matrix of multi‐port filtering power divider (FPD) with arbitrary phase shift, power division as well as reference impedances, for the first time. This method provides an attractive technique to synthesise a multi‐functional device that combines the characteristics of bandpass filter, multi‐port power divider and ideal phase shifters as well as the impedance matching network, which can effectively diminish the overall size and improve the performance of the microwave front‐end network. A newly defined coupling matrix corresponding to arbitrary multi‐port topologies that introduces ideal phase shift by virtue of constant frequency‐independent reactance at the source and load is developed in FPD synthesis process. The coupling matrix is obtained directly by optimising the presented cost‐function in this paper, avoiding complex similar transformation process of coupling matrix. Finally, several numerical examples of multi‐port FPD with equal/unequal power division ratio, arbitrary phase shift and reference impedances are synthesised to well verify the proposed synthesis method, and a practical example is given to verify the validity of arbitrary phase shift and arbitrary reference impedance.

Silicon photonics has evolved from lab research to commercial products in the past decade as it plays an increasingly crucial role in data communication for next‐generation data centers and high‐performance computing. Recently, programmable silicon photonics has also found new applications in quantum and classical information processing. A key component of programmable silicon photonic integrated circuits (PICs) is the phase shifter, traditionally realized via thermo‐optic or free‐carrier effects that are weak, volatile, and power hungry. A non‐volatile phase shifter can circumvent these limitations by requiring zero power to maintain the switched phases. Previously non‐volatile phase modulation is achieved via phase‐change or ferroelectric materials, but the switching energy remains high (pico to nano joules) and the speed is slow (micro to milliseconds). Here, a non‐volatile III‐V‐on‐silicon photonic phase shifter based on a HfO2 memristor with sub‐pJ switching energy (≈400 fJ), representing over an order of magnitude improvement in energy efficiency compared to the state of the art, is reported. The non‐volatile phase shifter can be switched reversibly using a single 100 ns pulse and exhibits excellent endurance over 800 cycles. This technology can enable future energy‐efficient programmable PICs for data centers, optical neural networks, and quantum information processing. [ABSTRACT FROM AUTHOR]

This paper proposes and demonstrates a novel filtering phase shifter with a compact size and good frequency selectivity using two dual composite right/left-handed (D-CRLH) resonators. Firstly, the study analyzes the D-CRLH structure to gain insights into its unique properties, providing a physical understanding for subsequent design procedures. Then, an ad hoc systematic design procedure for the D-CRLH phase shifter is discussed in detail. Different from the traditional phase shifter, the innovative integration of D-CRLH structure in phase shifters enables its advantages in the flexible realization of good in-band frequency selectivity and compact size. This advantageous utilization of the D-CRLH structure distinguishes our proposed phase shifter from conventional implementations. Finally, to demonstrate the feasibility of the proposed structure, we design, fabricate, and measure a prototype of the filtering phase shifter with a 90° phase shift. The comparison between simulation and measurement results shows good agreement, thereby confirming the effectiveness of both the new filtering phase shifter and the presented design procedure. Through this comprehensive investigation, our work showcases a promising solution for achieving compact size, good frequency selectivity, and reliable performance in phase shifter design. [ABSTRACT FROM AUTHOR]

• Independent displacer phase shifter (IDPS) for a two-stage pulse tube cooler is purposed in this manuscript. • Phase shifting mechanism of SDPS (stepped displacer phase shifter) and IDPS are analyzed, IDPS has a larger operating degree of freedom to providing different phase shifts for two stage cold finger. • A cooling power of 1.8 W at 20 K is obtained using IDPS, and the relative Carnot efficiency reaching 11.5 %, which is 16.9 % higher than the values obtained by the pulse tube cooler with SDPS. Phase shifter plays an important role in affecting cooling performance of pulse tube cooler (PTC). Warm displacer has been considered a very promising phase shifter due to phase shifting ability and work recovery. Independent displacer phase shifter (IDPS) for two stage PTC is purposed in this paper. Based on a two stage PTC, IDPS and a stepped displacer phase shifter (SDPS) have been comparatively investigated. Firstly, the phase shifting mechanism of two type displacers was studied. Numerical simulation was then conducted to investigated the effect of spring stiffness, moving mass and mechanical damper, and the optimal parameters of SDPS and IDPS were obtained. A cooling power of 1.8 W at 20 K was obtained with 220 W acoustic power input using IDPS, which is 16.9 % higher than that of SDPS. Next, Axial distributions of the phase difference and acoustic power were presented and discussed. In addition, exergy losses in each component were compared. IDPS presented the potential of achieving a higher cooling efficiency at lower temperature stage. [ABSTRACT FROM AUTHOR]

In this letter, a novel phase shifter with high selectivity is proposed and developed. It is divided into the main line together with the reference line. Firstly, the main line is a bandpass filter implemented by using the new coupled feed lines loading stub‐loaded coupled‐line resonators. Varying the coupling coefficient and the electrical length of the loaded branch can reasonably allocate the passband and transmission zeros/poles. Then, the reference line is a uniform microstrip line with an electrical length related to the phase shift degrees. Compared with conventional phase shifters, this phase shifter has the advantages of good frequency selectivity, as well as easy adjustment of the phase shift value. Finally, the phase shifter of 45°~180° are designed, simulated, and the value of 180° is fabricated and measured. The simulations are in good agreement with the actual measurements. [ABSTRACT FROM AUTHOR]

In this paper, a new 0.15–2 GHz broadband phase shifter with 9-bit phase resolution is presented. This broadband digital adjustable phase shifter is implemented by utilizing the signal vector summation technology. The phase shifter consists of one 90° hybrid coupler, two digital attenuators, two 180° hybrid couplers, two microwave switches, and one combiner. By adjusting the attenuation value of the two digital attenuators, the device creates a minimum 0.7° stepped phase shift. In addition, by switching the two microwave switches, a 360° range of phase shift is achieved while almost keeping the amplitude of the phase shifter constant. The measurement results show that the proposed phase shifter achieves a phase resolution of 0.7° while exhibiting an average insertion loss of 9 ± 2 dB and phase unbalance within ±10°. The calculated RMS phase error of the broadband phase shifter is below 5° from 0.15 to 2 GHz. [ABSTRACT FROM AUTHOR]

In this paper, a four unit cell micron-sized magnetic particles embedded composite right/left-handed (CRLH) transmission line metamaterial phase shifter is proposed. The variable phases are achieved by activating the micron-sized magnetic particles along the length of stub transmission lines of the CRLH transmission line structure. This causes to effectively change the inductance of stub transmission lines, which changes the phase of the RF signal. These structures can be activated in a symmetric or asymmetrical manner to obtain wide range of phase shifts. A prototype of cascaded four unit cell CRLH transmission line phase shifter with embedded silver-coated ferrites (magnetic particles) is designed, fabricated and tested for phase shifters applications. The measured phase response of the proposed phase shifter is in close agreement with the simulated phase response. Next, for the performance analysis of proposed phase shifter, a 1 x 4 conformal curved-shaped phased array operating at 5.8 GHz is fed with the four unit cell cascaded phase shifter in CST full-wave simulator. The conformal phased array with proposed integrated phase shifters was simulated for broadside pattern correction and main beam scanning at 20 degree on curved-shaped surface with different bend angles. The radiation pattern results obtained with the proposed integrated phase shifters are in close agreement with those obtained with direct excitation of the array. [ABSTRACT FROM AUTHOR]

This study presents a systematic design of an optimized drive signal control system for 2.5 GHz Doherty power amplifiers (DPAs). The designed system enables the analysis of the independent control of the amplitude and phase for the signals between the main and peak amplifiers of the DPA. The independent control of the signal is achieved by incorporating a variable attenuator (VA) and a variable phase shifter (VPS) in each of the two parallel paths of the DPA. This integration allows for driving varying power levels with an arbitrary phase difference between the individual parallel PAs for reduced control complexity and power consumption. The specific VA (Qorvo QPC6614) and VPS (Qorvo QPC2108) components are used for the test system to provide an amplitude attenuation range from 0.5 dB to 31.5 dB and a phase range from 0 ∘ to 360 ∘ at the intended operating frequency of 2.5 GHz, offering the benefit of characterizing the behavior of PAs for an extensive range of drive signals to optimize the output performance, such as PAE or the ACLR. For experimental validation, the designed drive signal control system is integrated with GaN PAs (Qorvo QPD0005—DUT) with a P 1 d B of 37.7 dBm. Each PA is preceded by a drive amplifier with a gain of 17.8 dB to boost the power fed into the PA. In this manuscript, we analyzed and compared the PAE of the DPA and parallel-connected PA for diverse input signals generated using a designed optimized control system. [ABSTRACT FROM AUTHOR]

This contribution presents the AM/AM and AM/PM characteristics of a 6-bit Phase and Amplitude Setting Circuit realized in Gallium Nitride technology and operating at the Ku band. A test bench, based on three vector receivers and an absolute power reference, has been purposely devised to capture the deviation with respect to the linear behavior (known by the S-parameters) for both the magnitude and the phase of the vector response. The complete 64-state constellation is reported up to a 37 dBm of input power level, at which the effects of the static AM/AM and AM/PM distortion become evident, with about 3 dB of gain compression and 2.7 deg of phase conversion. The key figure of merit of the proposed test bench is the capability of operating with very high driving power levels (potentially up to 41 dBm), with possible applications in phased arrays, AESAs, and other signal conditioning systems. [ABSTRACT FROM AUTHOR]

A linearization scheme is proposed for microwave photonic link to enlarge spurious free dynamic range using a dual-electrode dual parallel Mach–Zehnder modulator (MZM). This scheme employs phase control method to improve performance of the link by adjusting phase of radio frequency (RF) signals and bias voltages of optical modulator. Optical single sideband modulation is achieved through sub-modulators of dual parallel MZM which increases efficiency of the link. The simulated results show that third order intermodulation distortion is suppressed by 28 dB when the input RF signals are 9.1 and 9.5 GHz and noise floor is at −161 dBm/Hz. The spurious free dynamic range is also improved by 12.6 dB. [ABSTRACT FROM AUTHOR]

In this paper, we report the performance of a carrier depletion Silicon PIN phase shifter with over layer of 130 nm. It is observed that an optimum intrinsic gap of 250 nm for a device length of 5 mm at 2 V, resulted in Extinction Ratio (ER) of 23.41 dB and Bit Error Rate (BER) of 1.00 × 10−7 is obtained for 50 Gbps. The phase shifter is also designed for length 2 mm with an intrinsic gap of 100 nm at an operating voltage <4 V. The study also reveals that the proposed design for Mach-Zehnder modulator operating at a data rate of 100 Gbps for the concentration of P = 7 × 1017 cm−3 and N = 5 × 1017 cm−3 gives better BER and phase performance. The proposed design was also analysed in an intra-data centre communication setup of fibre length 15 km. [ABSTRACT FROM AUTHOR]

Two slabs of dielectrics with different values of refractive index are synthesized to form a composite structure and the whole system satisfies parity-time-reciprocal scaling symmetry. Four coherent-perfect-absorber-laser points are induced by modulating the incident wavelength of lightwaves and the loss/gain factor of materials. The locations of coherent-perfect-absorber-laser points in parameter space, which manifests the multi-wavelengths of coherent-perfect-absorber-lasers could be regulated by the incidence angle. Especially, a value of π phase shift in the transmitted/reflected light wave has been observed as well. This research has potential applications in multi-wavelength absorbers/lasers and half-wave phase shifters. [ABSTRACT FROM AUTHOR]