Electrical Phase Shift Research Articles

Photonic scheme to generate frequency 24-tupling mm-wave signal using three cascaded polarization modulators without filters

Abstract The paper proposes a new scheme for generating a frequency 24-tupling millimeter-wave (mm-wave) signal using three cascaded polarization modulators (PolMs). In the scheme, three polarization modulators with the cooperation of polarization controller (PC) and polarizer (Pol) in each subsystem are first employed to produce even order optical sidebands. Adjusting the angle of electrical phase shifters (EPS) to eliminate the unwanted even order optical sidebands except (6n)th order optical sidebands. Next, setting the modulation index to 4.968 to eliminate ±6th order sidebands. At last, adjusting the rotation angle of the polarizer placed behind the polarization beam combiner (PBC) to suppress 0th order optical carrier from the upper and lower branches. The obtained pure ±12th order sidebands are fed into the photodiode (PD) beat frequency. After detailed mathematical derivation and simulation verification, the accuracy of the scheme has been verified. The simulation results show that the optical sideband suppression ratio (OSSR) and the radio frequency spurious suppression ratio (RFSSR) can reach 54.49dB and 43.86dB, respectively. Moreover, the impacts of these non-ideal elements on OSSR and RFSSR are analyzed, and an admissible error extent is listed.

A Robust Super Twisting Controller Algorithm for Dual Star Induction Motor Based on Particle Swarm Optimization Algorithm

This research introduces an optimized control approach for a dual star induction motor (DSIM) using a combination of the Super Twisting Algorithm (STA) and Particle Swarm Optimization Algorithm (PSO) within the framework of indirect field-oriented control (IFOC) and two pulse width modulation (PWM) voltage sources. The primary aim of this study is to reduce torque fluctuations, minimize variations in stator current, and enhance the precision of speed control. The DSIM consists of two sets of three-phase windings with separate neutrals and a 30-degree electrical phase shift. The utilization of the STA control method addresses issues related to response time, steady-state error, and the impact of load disturbances, ultimately improving speed control. The Simulation conducted in MATLAB/SIMULINK are used to compare the performance of the proposed STA-PSO controller against a conventional Proportional-Integral (PI) controller. The outcomes demonstrate the substantial enhancements achieved by the STA-PSO controller in speed control, including reduced response time, improved steady-state error, and increased resilience against external disturbances. The proposed STA-PSO control strategy effectively mitigates torque and stator currents fluctuations in DSIM’s while offering superior speed control performance. These findings underscore the potential of the STA controller for enhancing control in various DSIM applications.

Optical-pulse-based reconfigurable phase control for independent beamforming and band fusion in a dual-band phased array receiver.

This Letter proposes an optical-pulse-based reconfigurable phase control method, enabling a dual-band phased array receiver to operate in two modes: dual-band-independent operation and dual-band fusion. The method utilizes optical pulses and optical delay to compensate for phase differences across frequency bands. An electrical phase shifter is employed to compensate for phase residual in both bands. All phase operations to both bands are processed concurrently in one link, thereby maintaining inter-band phase coherence. Experimental results verify the ability of dual-band-independent beamforming and inter-band phase coherence maintaining. A four-channel dual-band (X- and Ku-band) phased array antenna (PAA) receiver is constructed to measure PAA patterns and demonstrate band fusion. The pulse compression results in all directions reveal a doubled improvement in range resolution, which shows the potential for enhancement of radar performance.

Long distance QKD propagation using optical single sideband scheme

Implementation of the passive radio over-fiber technique permits modulating the low-frequency sub-carrier onto an optical channel for dissemination through a light-wave fiber network. Single-sideband modulation for optical signals allows the impressive utilization of channel capacity in optical fiber. Dispersion reduction techniques limit the pulse spreading of a propagated signal in any photonic scheme. To control pulse-spreading effects, the optical single-sideband modulation technique at different phase shifts is modeled, analyzed, and compared to examine the performance of a sub-carrier multiplexing system. Hence, in this paper, a quantum key distribution network using a single sideband modulation technique based on a Li-Nb Mach-Zehnder modulator has been proposed at different electrical phase shifts. In this suggested model, the Optisystem 14.2 simulator is used to analyze the nonlinear characteristics. We have designed a single-sideband contour reduction and amplification with each couplet of 120 km by increasing the distance up to 720 km, and the phase between quantum states is determined. The system performance of the suggested model is investigated and compared based on output power (dBm), quality factor, eye diagram, bit error rate (BER), extinction ratio (ER), and optical spectrum of the received signal by varying link distance (km), channel spacing (nm), input power (dBm), and fiber dispersion (ps/ns/km).

Design and investigation of filterless sixtuple RoF upconversion system with improved sideband to carrier suppression ratio using MZM extinction ratio variance

Abstract In this work, millimeter wave generation of sixtuple frequency scheme using dual parallel Mach–Zehnder modulator configuration has been investigated. The proposed scheme is mathematically analyzed and its performance is evaluated using software optisystem v.18. The vital parameters of both Mach–Zehnder modulator and phase of radio frequency local oscillator are properly adjusted for upconversion of 10 GHz radio frequency drive signal into 60 GHz mm wave. The impact of Mach–Zehnder modulator extinction ratio on radio frequency sideband suppression ratio, optical sideband suppression ratio and third sideband to carrier suppression ratio, is evaluated. An improved 63 dB third sideband to carrier suppression ratio is achieved at increased extinction ratio of Mach–Zehnder modulator. Impact of bias point drift and electrical phase shift on sideband suppression ratios are evaluated. Further, millimeter wave signal of 6–60 GHz tunability is realized by applying radio frequency local oscillator signal from 1 to 10 GHz.

Image-Rejected Multi-Band Frequency Down-Conversion Based on Photonic Sampling

An image-rejected multi-band frequency down-conversion scheme is proposed and experimentally demonstrated based on photonic sampling. The multi-band radio-frequency (RF) signals to be processed are copied into two replicas in quadrature, which are then sampled by an ultra-short optical pulse train via a polarization-multiplexed modulator. After polarization demultiplexing and detection using a pair of low-speed photodetectors, the multi-band RF signals are simultaneously down-converted to the intermediate frequency (IF) band. The image components can be suppressed by quadrature coupling the two generated IF signals via an electrical 90° hybrid coupler (HC). In the experiment, multi-band RF signals in the frequency range of 6 GHz to 39 GHz are down-converted to the IF band below 4 GHz using a local oscillator (LO) signal at 8 GHz to generate the ultra-short optical pulse train. Image rejection is achieved in the digital domain using digital signal processing to compensate for the amplitude and phase mismatch between the two IF signals and to implement quadrature coupling. In addition, through using an electrical phase shifter, an electrical attenuator, and an electrical 90° HC to achieve quadrature coupling of the two IF signals, image-rejected multi-band frequency down-conversion is also verified in the analog domain.

A dual parallel Mach–Zehnder modulator linearization scheme based on 90° phase shifters

Abstract In this paper, a dual-drive dual-parallel Mach–Zehnder Modulator based linearization scheme is implemented by utilizing only two phase shifters and comprehensively demonstrated for a photonic transmission link. Third order intermodulation distortion is suppressed by adjusting angles of electrical phase shifters i.e. π/2 and−π/2 and a non-linear distortion immune system can be proposed for microwave photonic link. A complete suppression in intermodulation terms and 20.8 dB enhancements are found in spurious free dynamic range (SFDR). SFDR reaches 135.6 dB Hz4/5 by suppressing major spurious contributors of third order intermodulation distortions in optical domain only which ensures the improvement in performance of link against non-linear terms.

Circuit analogue of relativistic aberration of light using low-cost, low-complexity operational amplifier-based all-pass filters

We propose, simulate, and experimentally demonstrate a circuit analogue of a special relativity phenomenon known as relativistic aberration of light (RAL) by using a surprisingly simple, low-cost, and easily accessible electronic circuit-based all-pass filter. This work is useful for two audiences: (i) physicists who are interested in research on circuit analogues; and (ii) physics educators who are interested in using the research results to raise interest among students by incorporating analogue-based learning into undergraduate physics lecture and laboratory courses. For the first type of audience, we present a rigorous theoretical framework describing this RAL-on-an-electronic-chip analogy. We show by (i) analytical modelling, (ii) commercial circuit software simulation, and (iii) experiment that the electrical phase shift Φ of the output signal is analogous to the RAL angle, Ψ. This parameter opens up a path among researchers to model the effects of other relativistic phenomena with electronic circuits. For the second type of audience, we discuss the potential role of RAL-on-an-electronic-chip in physics education (both in lectures and laboratory) that combines students’ learnings of both physics and electronic circuits, at the same time. We also explore briefly its relevance to engineering education.

Design optimisation and performance investigation of novel dual three‐phase permanent‐magnet linear synchronous machines for a ropeless elevator system

A novel dual three-phase permanent-magnet linear synchronous machine (DTP-PMLSM) is proposed for the large capacity ropeless elevator, where two sets of windings have 30 electrical degrees phase shift in space. First, the topology of DTP-PMLSM with 12-slot/11-pole (12 s/11p) combination is introduced. Second, the influence of each main parameter on thrust force performance is investigated by single variable sweeping method, and then DTP-PMLSM is optimised by global optimisation method. Moreover, the electromagnetic performance is predicted and analysed by two-dimensional (2D) finite element method (FEM) in detail. Compared with conventional single three-phase PMLSM, the proposed DTP-PMLSM shows better force performance. Furthermore, the analysis results are compared with 3D FEM which includes the transverse end effect. Finally, a 12 s/11p prototyped machine is built and tested to validate the theoretical analyses.

Моделирование режима упора асинхронизированного вентильного двигателя с питанием от инвертора напряжения

The paper presents the results of mathematical modeling of a sensorless electric drive control system operation. This system is based on a dependent voltage inverter with current phase control and phase-locked loop frequency control and feeds an asynchronous valve motor in the stop mode. The article presents the developed model of this electric drive in the MATLAB mathematical modeling system. The model features an excitation frequency converter, that maintains a nominal rotor current and a constant excitation frequency of 15 Hz. From the stator (armature) side, the frequency converter is synchronized in phase with the current using an automatic frequency control unit and sets the phase angle between the current and the armature voltage. The paper presents a basic system of equations that describes the modes of operation of an asynchronized valve motor, as well as the expression of the electromagnetic moment in the stop mode. It shows the electromagnetic torque on the motor shaft, which was obtained as a result of mathematical modeling of the thrust mode of an asyn­chronized valve motor at rated currents, the rotor frequency of 15 Hz, with 20 electrical degrees phase shift between the current and the armature voltage.

Photonic full-range phase shifter with simultaneous tunable frequency multiplying capability based on a DMZM

In this paper, a novel microwave photonic full-range phase shifter with simultaneous frequency-multiplying capability is proposed. The main device is a dual-drive Mach–Zehnder modulator (DMZM) embedded in a Sagnac loop. Under the assistance of two electrical phase shifters (EPS) and a following polarizer (Pol), the optical carrier is eliminated with desired phase tunable carrier-suppressed double-sideband (CS-DSB) signal reserved. So after photoelectric conversion, the frequency-multiplied phase tunable signals are generated. The frequency multiplication factor (FMF) switching and phase tuning operation of multiplied signals can be achieved easily by adjusting the corresponding EPS. The simulation results show that the proposed structure driven by a 10 GHz RF signal can generate a frequency-doubled signal (20 GHz) or frequency-quadrupled signal (40 GHz) that features full-phase tunable range and flat power response. What is more, the proposed phase shifter has a relatively good robustness to the non-ideal factors, large frequency operation range and good frequency tunable capability.

Performance analysis on a filter-less frequency doubling generator with tunable phase shift based on dualpolarization modulation

A filter-less frequency doubling generator with tunable phase shift based on dual-polarization modulation is proposed and analyzed. The setup is composed with a continuous-wave laser, a dual-polarization Mach-Zehnder modulator and a linear polarizer followed by a photodetector. The modulator is used to generate frequency doubling modulation signals on orthogonal polarization axis. By tuning the polarization state before the polarizer, the initial phase of the generated microwave signal can be tuned manually. At the meantime, the signal amplitude will remain constant. It is found the generated signal’s frequency is twice of the driven frequency. The electrical phase shift can be tuned within full range ((0°—360°). Without using any optical filter or wavelength-dependent component, this scheme is featured with good frequency tunability and multi-wavelength operation.

A simplified optical millimeter-wave generation scheme based on frequency-quadrupling

This paper analyzes and demonstrates a simplified frequency quadrupling configuration for optical millimeter-wave (mm-wave) generation, in which the electrical phase shifter and optical filter are omitted. Theoretical analysis is given to reach the optimum operating conditions including direct current (DC) bias voltage, optical transmission point of the dual-parallel Mach-Zehnder modulator (MZM) bias voltage, optical transmission point of the dual-parallel Mach-Zehnder modulator (DP-MZM), amplitude of the radio frequency (RF) driving signal and the impact of the extinction ratio (EF) on the optical sideband suppression ratio (OSSR) and radio frequency spurious suppression ratio (RFSSR). Experiments prove an OSSR of 15 dB and an RFSSR of 26 dB for the new frequency quadrupling scheme at 6 GHz, 8GHz and 10 GHz of RF driving signal without any electrical phase shifter or optical filter. This system exhibits the advantage of low wavelength dependence and large frequency tunable range.

Design of Coplanar Slotted SIW Antenna Arrays for Beam-Tilting and 5G Applications

A new solution for feeding the engraved slot antennas based on the substrate integrated waveguide (SIW) technology is presented in this letter. The structure is designed to operate at 25 GHz for beam-tilting and fifth-generation applications. Here several passive SIW slot antennas are proposed to cover an area from −56° to +56° with an offset of 10° at the operating frequency without using any phased shifter, in order to limit the losses. This new feeding approach is developed by using associated SIW holes to excite differently the centered slots located on the SIW structure broad face via coplanar lines. The electrical phase shifts are controlled by the position and number (one or two) of coplanar lines, and the combined slot configurations achieve beam-tilting function.

Photonic phase shifter with full tunable range and multi-band frequency-conversion feature based on a PDM-DPMZM

In this paper, a novel photonic phase shifter with − 180° to 180° phase-tunable range and multi-band frequency-conversion feature is proposed. The main device is a single polarization division multiplexing dual-parallel Mach–Zehnder modulator (PDM-DPMZM). The PDM-DPMZM is employed to generate an optical frequency comb (OFC) and a carrier-suppressed single sideband (CS-SSB) in two mutually orthogonal polarizations. Simultaneously, an electrical phase shifter is adopted to control the initial phase of the CS-SSB. The simulation results show, a RF signal with the frequency of 4.3 GHz (C-band) can be down-converted to 1.4 GHz (L-band). Meanwhile, it can also be up-converted to 5.7 GHz (C-band), 10 GHz (LO signal), 14.3 GHz (Ku-band) and 18.6 GHz (K-band) with their phases continuously tuned from − 180° to 180°. Furthermore, the proposed structure features flat power response, frequency-independent operation, simple configuration, easy phase tuning, better ability to cope with DC drift and wide operation bandwidth. The unwanted signal suppression ratio (USSR) and the spurious free dynamic range (SFDR) of the phase shifter are also studied.

A simple and tunable photonic generation of frequency-doubled triangular waveform based on two cascaded modulators

A simple and tunable photonic approach for frequency-doubled triangular waveform generation is proposed and experimentally demonstrated. The approach is based on an intensity modulator (IM) and a cascaded polarization division multiplexing Mach–Zehnder modulator (PDM-MZM). The IM and the upper arm of the PDM-MZM are driven by the same LO signal, with the former biased at the null point and the latter at the maximum transmission point. By adjusting the modulation index of the upper arm and the direct current (DC) bias of the lower arm of the PDM-MZM, the frequency-doubled full-duty-cycle triangular waveform can be generated. The proposed approach does not use any electrical phase shifter or optical filter, it is easy to implement and exhibits the advantages of good frequency tunability. An experiment is conducted to verify the approach. Triangular waveforms with different repetition rates of 8 GHz and 10 GHz are generated.

Photonic generation of binary phase-coded microwave waveforms and phase-coded pulses with ultrawide frequency tunable range

A scheme that can produce a continuous wave (CW) phase-coded signal and phase-coded pulses is proposed. The proposed scheme is based on a dual-polarization Mach–Zehnder modulator (DPol-MZM), a polarization modulator (PolM) and a balanced photodetector (BPD) without the help of an electrical phase shifter or an electrical power divider. In DPol-MZM, a carrier-suppressed double sideband (CS-DSB) signal and an optical carrier are, respectively, produced in the upper and lower arms, which are in two orthogonal polarization states. The output is then sent to a PolM. The polarization multiplexed CS-DSB and optical carrier are phase modulated by driving the RF port of the PolM with a coding signal. After beating between the modulated CS-DSB and optical carrier in a BPD, a stable CW phase-coded signal or phase-coded pulses can be obtained. The proposed scheme is experimentally verified. Phase-coded microwave waveforms at 6 and 11 GHz are generated and phase-coded pulses at 11 GHz are also produced.

A Radio over Fiber (RoF) Based Single Sideband Modulated Passive Optical Network (PON) Using Mach Zender Modulator Based on Different Electrical Phase Shifts

Abstract This research work provides an insight on a radio over fiber (RoF) based passive optical network (RoF-PON) utilizing two diverse electrical phase shifts with optical single sideband modulation (OSSB) by exploiting Mach Zender modulator. The influence of chromatic dispersion (CD) in PONs employing single mode fiber (SMF) is a noteworthy issue and should be limited. The two techniques of OSSB modulation, in view of the two distinct angles of the hybrid coupler are employed for the design and implementation of RoF-PON. The RF signal is partitioned into two ways equally before applying it to the dual drive Mach Zender modulator input, utilizing an electrical hybrid coupler that imparts two discrete phase shifts of 90° and 120° to generate two OSSB signals individually. By utilizing traditional OSSB technique having 90° phase shift, either of the first-order sideband (lower or upper first order) suppression occurs yet second-order harmonics are still existent in the system. As opposed to this, the OSSB technique using 120° phase shift causes the suppression of either lower first order and higher second order sideband or vice versa. When contrasted to the PON based on traditional technique (90° phase shift technique), the suppression of second order sideband in PON using 120° technique lessens the system CD. Hence the PON based on 120° phase shift technique has enhanced functionality in terms of system BER, received power and power losses as compared to that with traditional OSSB technique.

Time-dependent Aharonov–Bohm effect on the noncommutative space

We study the time-dependent Aharonov-Bohm effect on the noncommutative space. Because there is no net Aharonov-Bohm phase shift in the time-dependent case on the commutative space, therefore, a tiny deviation from zero indicates new physics. Based on the Seiberg-Witten map we obtain the gauge invariant and Lorentz covariant Aharonov-Bohm phase shift in general case on noncommutative space. We find there are two kinds of contribution: momentum-dependent and momentum-independent corrections. For the momentum-dependent correction, there is a cancellation between the magnetic and electric phase shifts, just like the case on the commutative space. However, there is a non-trivial contribution in the momentum-independent correction. This is true for both the time-independent and time-dependent Aharonov-Bohm effects on the noncommutative space. However, for the time-dependent Aharonov-Bohm effect, there is no overwhelming background which exists in the time-independent Aharonov-Bohm effect on both commutative and noncommutative space. Therefore, the time-dependent Aharonov-Bohm can be sensitive to the spatial noncommutativity. \draftnote{The net correction is proportional to the product of the magnetic fluxes through the fundamental area represented by the noncommutative parameter $\theta$, and through the surface enclosed by the trajectory of charged particle.} More interestingly, there is an anti-collinear relation between the logarithms of the magnetic field $B$ and the averaged flux $\Phi/N$ (N is the number of fringes shifted). This nontrivial relation can also provide a way to test the spatial noncommutativity. For $B\Phi/N\sim 1$, our estimation on the experimental sensitivity shows that it can reach the $\rm 10GeV$ scale. This sensitivity can be enhanced by using stronger magnetic field strength, larger magnetic flux, as well as higher experimental precision on the phase shift.

Dielectric properties of α-Fe1.6Ga0.4O3 oxide: A promising magneto-electric material

We prepared the samples of α-Fe1.6Ga0.4O3 by mechanical alloying of α-Fe2O3 and β-Ga2O3 and subsequent vacuum annealing. The electrical conductivity and dielectric constant in Ga doped hematite samples is enhanced with respect to α-Fe2O3. In this work, we present dielectric properties of the Ga doped system by recording the frequency dependent electrical conductivity, impedance, modulus, dielectric constant, and phase shift in a wide temperature range. We observed electrical contribution from grain part is more conductive and capacitive in comparison to the grain boundary contribution of the samples. Temperature variation of the dielectric parameters has shown transformation of the conductivity states (semiconductor ↔ metal like ↔ semiconductor) in the samples. The conductivity and dielectric constant curves have shown an anomalous peak at about 300 K for all the samples. Dielectric loss curves indicated coexistence of conduction process and dielectric relaxation process in the samples. The temperature dependence of phase shift shows that conductive effect dominates above 400 K, where as capacitive effects dominate below 400 K. It appeared that dielectric properties below 400 K are correlated with the change of magnetic spins order from canted ferromagnetic to weak antiferromagnetic state in the samples. The studied system is a new class of material where magnetic spin order affects the dielectric properties. The results could be useful for understanding the properties in non-traditional magneto-electric systems.