Microwave Phase Shifter Research Articles

Ultra-Low Phase Noise Measurement of Microwave Sources Using Carrier Suppression Enabled by a Photonic Delay Line

We propose and demonstrate a photonic delay line based carrier suppression interferometer system for measuring the phase noise of microwave sources. We show both theoretically and experimentally for the first time that carrier suppression is capable of suppressing the effects of the residual phase noise of the microwave amplifiers and the relative intensity noise of light in the system by up to 70 dB, and therefore effectively eliminates the contributions of these noise sources to the noise floor of the phase noise measurement system. Using a 2-km photonic delay line, we achieved phase noise measurement floors of −126 dBc/Hz at 1 kHz and −152 dBc/Hz at 10 kHz around a 10 GHz carrier, respectively, which are 15 and 20 dB lower than those of a frequency discriminator based phase noise measurement system using the same length of fiber delay and the same optical and microwave components. The noise floor of −152 dBc/Hz at 10 kHz is also 8 dB and 17 dB lower than those of a Keysight E5052B phase noise measurement system with 100-times cross-correlation and without cross-correlation, respectively. Even lower phase noise floors are expected for such a carrier suppression system if microwave phase shifters with lower residual phase noise or a longer photonics delay line are used.

Dispersive readout of room-temperature ensemble spin sensors

We demonstrate dispersive readout of the spin of an ensemble of nitrogen-vacancy centers in a high-quality dielectric microwave resonator at room temperature. The spin state is inferred from the reflection phase of a microwave signal probing the resonator. Time-dependent tracking of the spin state is demonstrated, and is employed to measure the T 1 relaxation time of the spin ensemble. Dispersive readout provides a microwave interface to solid state spins, translating a spin signal into a microwave phase shift. We estimate that its sensitivity can outperform optical readout schemes, owing to the high accuracy achievable in a measurement of phase. The scheme is moreover applicable to optically inactive spin defects and it is non-destructive, which renders it insensitive to several systematic errors of optical readout and enables the use of quantum feedback.

Photonic-Assisted Microwave Frequency and Phase Shifter for Deception Jamming

A new microwave photonic signal processing structure that has the ability to realise frequency and phase shifting operation is presented. The proposed structure uses Serrodyne phase modulation in a dual-polarisation binary phase shift keying (DP-BPSK) dual-drive Mach Zehnder modulator to shift the frequency of an input microwave signal. This has the advantage over the conventional frequency mixers that the unwanted frequency components adjacent to the frequency translated microwave signal can be largely suppressed. It is suitable for use in deception jamming in electronic countermeasures systems. The phase shifting operation is realised by controlling the bias voltages of the DP-BPSK modulator. The dual-function microwave photonic signal processor has a simple structure and a wide bandwidth. The structure enables commercial modulator bias controllers to be used to provide long-term stable performance. Experimental results are presented that demonstrate a wide operating frequency range of 3 to 16 GHz, an over 35 dB suppression on the spurious signals and 0° to 360° phase shift on the frequency translated microwave signal. Using bias controllers to maintain a large spurious suppression ratio of around 35 dB is also demonstrated.

Nickel and gold identification in p-type silicon through TDLS: a modeling study

In Silicon, impurities introduce recombination centers and degrade the minority carrier lifetime. It is therefore important to identify the nature of these impurities through their characteristics: the capture cross sectionσand the defect levelEt. For this purpose, a study of the bulk lifetime of minority carriers can be carried out. The temperature dependence of the lifetime based on the Shockley-Read-Hall (SRH) statistic and related to recombination through defects is studied. Nickel and gold in p-type Si have been selected for the SRH lifetime modeling. The objective of the analysis is to carry out a study to evaluate gold and nickel identification prior to temperature-dependent lifetime measurements using the microwave phase-shift (μW-PS) technique. The μW-PS is derived from the PCD technique and is sensitive to lower impurity concentrations. It has been shown that both gold and nickel can be unambiguously identified from the calculated TDLS curves.

Enhanced structural and dielectric properties of calcium and chromium based M-type hexagonal ferrites

M-type hexaferrites with composition Ca1−xCrxFe12O19 were synthesized by the sol–gel auto-combustion method. Structural, morphological and dielectric properties were explored. Annealing of the samples was done at 1200 °C for 8 h. XRD pattern reveals single-phase magnetoplumbite structure. The structural properties as lattice parameters, crystallite size and cell volume of Ca1−xCrxFe12O19 hexaferrites were evaluated. Crystallite size of the particle varied from 45.85 to 42.96 nm. Morphology of the samples observed by scanning electron microscopy reveals regular platelet hexagonal structure and all the grains were distributed homogeneously. Dielectric parameters such as dielectric loss, dielectric constant, tangent loss, electric modulus, ac conductivity and Q values of the prepared samples were also discussed. These measured dielectric parameters are appropriate for high-frequency applications such as microwave absorber, phase shifter, dielectric resonator and stealth technology.

Fast-Reconfigurable Microwave Photonics Phase Shifter Using Silicon Microring Resonators

Thermally controlled silicon photonics microwave phase shifters suffer from slow reconfiguration time that practically limits their application fields. A microwave photonics phase shifter exploiting fast plasma dispersion effect in a silicon microring resonator (MRR) embedding a laterally-doped pn-junction waveguide operating in carrier-depletion mode has been designed and characterized. Proper dimensioning of ring parameters allows moderate insertion loss and limited RF power excursion in correspondence of wide RF phase changes as the space charge region of the junction is modulated by an applied reverse voltage. Experimental results confirm a large modulation bandwidth of more than 5GHz and a phase excursion well in excess of 360° using a cascaded MRRs pair with a residual amplitude modulation down to 2.3 dB.

Measurement of Propagation Characteristics of Nonreciprocal Networks/Lines Using a Line–Line Method

In this article have proposed a new calibration-free line–line method for propagation constant ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\gamma$</tex-math></inline-formula> ) determination of homogeneous nonreciprocal networks or lines with symmetric reflection property. To achieve our goal, wave-cascading matrices for impedance, amplitude, and phase changes for a line step from a homogeneous reciprocal network or line to a homogeneous nonreciprocal network or line (and vice versa). Two different approaches based on the proposed line–line method are proposed for unique extraction of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\gamma$</tex-math></inline-formula> in forward and backward directions. Measurements of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\gamma$</tex-math></inline-formula> for two reciprocal lines (waveguide straights at X-band and Ku-band with different lengths) and a nonreciprocal line (microwave phase shifter) were first carried out and then compared with measured <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\gamma$</tex-math></inline-formula> of these lines by different methods to validate our method and monitor its accuracy.

Propagation constant measurements of reflection-asymmetric and nonreciprocal microwave networks from S-parameters without using a reflective standard

Abstract We propose a simple method for determination of forward and backward propagation constants of nonreciprocal uniform networks or lines with asymmetric reflections. The wave cascading matrix presentation is used to diagonalize and decompose the line in terms of impedance and amplitude/phase transitions. The proposed method uses scattering parameters of the line/network connection and the thru connection, thus eliminating errors arising from fabrication tolerance and thickness of the second line. Besides, compared with conventional methods which necessitate calibration techniques such as the thru-reflect-line, our method has the advantage that it determines propagation constants without resorting the measurement of any reciprocal reflective standard. Propagation constant measurements of a reciprocal network (different-length X-band waveguide straights) and a nonreciprocal network (microwave phase shifter) were first carried out and then compared with those measured by different methods to validate and monitor the accuracy of our method.

A filterless reconfigurable frequency mixer based on a wideband photonic microwave phase shifter

In this paper, a filterless reconfigurable frequency mixer based on a wideband photonic microwave phase shifter is proposed. The main device is a single PDM-DPMZM which is applied to generate a pair of orthogonally polarized CS-SSB signals. A pair of PCs are followed to introduce a tunable phase to the CS-SSB signals. By changing the detection scheme of the output optical signals and tuning the PCs, single-ended, double-balanced, I/Q, and image-reject mixer can all be achieved with the capability of full range phase shifting. And it can also perform frequency up- and down-conversion switching by adjusting the DC biases of the modulator. A simulation is carried out to demonstrate its versatility, flexibility and reconfigurability. The measured image-rejection ratio of the image rejection mixer is about 65 dB. In addition, the frequency operation range, practical applicability and feasibility are discussed. The effect of non-ideal factors or adjustable parameters, i.e., extinction ratio deterioration, DC biases drift, phase inaccuracy between I/Q path, instability or inaccuracy of the PC and LO signal power variation on system performance are also analyzed.

Broadband Image-Reject Mixing Based on a Polarization-Modulated Dual-Channel Photonic Microwave Phase Shifter

Broadband image-reject mixing using a dual-channel polarization-modulated photonic microwave phase shifter is proposed and experimentally demonstrated. The polarization-modulated photonic microwave phase shifter is realized by an orthogonal circularly-polarized wavelength generator, an optical coupler, two polarizers, and two photodetectors (PDs). When a local oscillator (LO) signal, a radio-frequency (RF) signal, and an image interference are supplied to the polarization-modulated phase shifter, opposite phase shifts would be introduced to the RF- and image-induced intermediate frequency (IF) signals. By carefully adjusting the polarizers to make the two channels of the phase shifter quadrature, a phase difference of −90 degree is introduced to the RF-induced IF signals in the two channels, while 90-degree phase difference between the image-induced IF signals is produced. With an electrical 90 degree hybrid to combine the two channels, the two RF-induced IF signals will be in phase while those from the image are out of phase. As a result, the image in the downconverted signal is cancelled. An experiment is carried out. An image-reject mixer (IRM) with an image rejection ratio of ∼60 dB for a single-frequency signal and 23 dB for a 4-GHz linear frequency-modulated signal is obtained.

Broadly tunable and low power penalty radio frequency phase shifter using a coupled silicon microcavity.

We present a continuously tunable silicon photonics assisted radio frequency (RF) phase shifter using a coupled microring resonator. Using the coupled cavity, we demonstrate a sub-1 dB power penalty for a RF bandwidth of 34.5 GHz (9-43.5 GHz) and a phase shift of π over the reported frequency range. Rigorous optimization of the cavity design using the coupled-mode theory is carried out to realize ultranarrow resonance peaks with a low-extinction ratio and large phase shift. Thermal tuning of the cavity is used to tune the phase while all-optical tuning is exploited to achieve broadband operation. We present a detailed simulation and experimental study of the proposed configuration. The proposed device configuration exhibits a configurable resonance linewidth and extinction ratio that allows for a broad bandwidth and an extremely low power penalty microwave phase shifter. We believe the demonstration would allow better integration of the on-chip functional elements of integrated microwave photonics.

Single parallel stubs as broadband microwave phase shifters

Single parallel stubs as broadband microwave phase shifters

Magnetoelectric Composites: Modeling and Application

The progress in electronic technology is directly coupled with the advances made in materials science. Within the broad class of materials available today, functional materials provide unique opportunity for developing novel components and devices as their physical and chemical properties. A combination of ferromagnetic and ferroelectric materials provides a new class of functional materials, termed as magnetoelectrics. An overview of modern magnetoelectric composites and examples of the design of electronic devices based on them are presented. The feature of these materials is that their parameters changes under the influence of an external magnetic and electric fields. The behavior of magnetoelectric composites in the wide frequency range is considered. Modeling of ME composites at low frequencies and in the field of electromechanical, ferromagnetic and magnetoacoustic resonances has shown that they can be effectively used to design various electronic devices in a wide frequency range. Nomographs method which can be used to plot the ME parameters versus initial material parameters and component volume fractions is presented. Nomographs can be used for a quick test of ME composites for applications where an approximate answer is appropriate and useful. Examples of ME composites application such as: magnetic field sensors, current sensors, microwave phase shifters, filters, attenuators, isolators are presented.

Integrated tunable phase shifter based on energy-conserved phase amplification and its application for RF-OAM generation

Photonics-assisted microwave phase shifter is one of the essential components in communications. Phase amplification is a promising technology which efficiently enables compact photonics-assisted microwave phase shifter. Based on vector sum, the phase shift can be translated from amplitude attenuation to phase amplification. This issues an additional optical energy consumption and even more the highly dependent signal to noise ratio of phase-shifted microwave signal. In this paper, we propose an energy-conserved phase amplification concept to address this issue. Furthermore, based on this concept, we demonstrate a microwave photonic phase shift system with an integrated chip incorporating an arrayed waveguide gratings (AWG) structure. A multichannel continuous 360° phase shift over a frequency range of 12 GHz–20 GHz can be achieved by changing the optical carrier wavelength. Taking advantages of phase modulator and AWG structure, a reliable and efficient phase shifter for beam steering and orbital angular momentum (OAM) generation system can be realized without any other active device. The simulation results of OAM purity test show that better OAM beams can be obtained with the proposed phase shifter. This integration method has great potential in RF OAM generation and multiplexing system to improve the signal quality and reduce the system complexity.

Photonic microwave frequency down-converter with image rejection via carrier suppression single sideband modulation and photonic microwave phase shift

ABSTRACTThe combined use of carrier suppression single sideband (CS-SSB) modulation and photonic microwave phase shift is described and analyzed to realize microwave frequency down-conversion with image rejection. Based on the idea of phase cancellation, the image signals have identical amplitude and opposite phase to be suppressed, while the useful signals have identical amplitude and phase through an electrical 90 degree hybrid to be strengthened. The approach is investigated in theory and demonstrated using simulation. It is shown that the power of the useful IF signal is nearly 60 dB larger than that of the image IF signal. Besides, the zero-IF receiving capability of our approach has been also investigated when a modulated RF signal with different format input. The 2.5 Gbit/s RF modulated signals centred at 15 GHz with quadruple-, 8-, 16- phase shift keying (QPSK, 8PSK, 16PSK), and 16-quadrature amplitude modulation (16QAM) formats are successfully demodulated with good error vector magnitudes (EVMs) and constellation diagrams in wide power range of input RF carrier.

Brillouin-based phase shifter in a silicon waveguide

Integrated silicon microwave photonics offers great potential in microwave phase shifter elements, and promises compact and scalable multi-element chips that are free from electromagnetic interference. Stimulated Brillouin scattering, which was recently demonstrated in silicon, is a particularly powerful approach to induce a phase shift due to its inherent flexibility, offering an optically controllable and selective phase shift. However, to date, only moderate amounts of Brillouin gain has been achieved and theoretically this would restrict the phase shift to a few tens of degrees, significantly less than the required 360 degrees. Here, we overcome this limitation with a phase enhancement method using RF interference, showing a 360 degrees broadband phase shifter based on Brillouin scattering in a suspended silicon waveguide. We achieve a full 360 degrees phase-shift over a bandwidth of 15 GHz using a phase enhancement factor of 25, thereby enabling practical broadband Brillouin phase shifter for beam forming and other applications.

High-speed and high-precision torsion sensor based on polarization-induced microwave photonic phase shift measurement.

We propose and experimentally demonstrate a technique to achieve high-speed and high-precision torsion sensing based on polarization-induced microwave photonic phase shift measurement. In the proposed system, a section of single-mode fiber (SMF) is used as a sensor that is incorporated into a microwave photonic phase shifter (MPPS). The MPPS consists of a laser source, a polarization modulator (PolM), an optical bandpass filter (BPF), a SMF, a polarizer, and a photodetector (PD). The phase shift of the microwave signal is a linear function of the twist angle of the SMF. An IQ detection module is utilized to measure the microwave phase shift. The performance of the proposed torsion sensor is experimentally evaluated. A measurement range of over 180° and a sensing accuracy of 0.03° are realized at an ultrahigh speed of 1MHz, with low strain and temperature cross-sensitivity.

Fabrication and characterization of microwave phase shifter in microstrip geometry with Fe film as the frequency tuning element

Abstract A series of ultra-small planar broad-band phase shifters with wide range of phase shift are designed and tested in this investigation. To achieve this performance a series of microstrip transmission lines with Iron (Fe) films of various thicknesses (from 100 to 800 nm) were designed, fabricated and tested. The basic principle of operation of these phase shifters are based on ferromagnetic resonance (FMR). The influence of the thickness of the magnetic layer was studied for two frequency regions: below and above the ferromagnetic resonance. This is because for a real-device the insertion loss should be less than −3 dB (or as low as possible). In the high frequency region, the optimal frequency (corresponding to the highest change in phase shift) increased significantly with the increase of the Fe film thickness (from 27 GHz for the structure with 100 nm of Fe to 43 GHz for the structure with 800 nm of Fe film). In the low frequency region, however, the optimal frequency varied little with the Fe layer thickness. The highest change in phase shift (~90 deg/cm) corresponded to the structure with the thinnest Fe layer for the low frequency region and with the thickest Fe layer for the high frequency region. In the high frequency region the Figure-of-Merit was about 20 deg/dB at low magnetic fields (

Simple and Flexible Photonic Microwave Waveform Generation With Low RMSE of Square Waveform

A simple and flexible photonics-assisted approach based on an integrated polarization-division multiplexing Mach–Zehnder modulator (PDM-MZM) and a balanced photodetector (BPD) to generating microwave waveform is proposed. The sub-MZMs of PDM-MZM are biased at peak and null points. Square and trapezoid waveforms are generated by controlling the PC and driven sinusoidal signal power. Triangle and sawtooth waveforms are also obtained with the help of a 90° microwave phase shifter (MPS). The proposed approach features simple structure, flexible frequency tunability, and easy implementation. Moreover, the problem of high root-mean-square error (RMSE) of square waveform is solved by this approach for the first time. An experiment is conducted to verify the approach. Different waveforms with the repetition rates of 3 and 5 GHz are generated. The RMSE of square waveform is reduced from 0.3328 to 0.2048 which is the lowest RMSE to the best of our knowledge.

Photonics-Assisted Super-Octave Microwave Phase Shifter

A photonics-assisted super-octave microwave phase shifter is proposed. The super-octave frequency range is achieved by eliminating the second-order distortions (SDs) with the techniques of polarization interleaving and second-order optical sidebands (2-OSBs) phase processing. Polarization interleaving is based on a polarization-multiplexing dual-drive Mach-Zehnder modulator (PM-DMZM) and single sideband with carrier (SSB+C) modulation. 2-OSBs phase processing is implemented by introducing opposite phase shifts to the ±2-OSBs in a Fourier-domain optical processor (FD-OP). The proposed phase shifter is experimentally verified by proof-of-concept experiments. Experimental results show that flat phase shifts cover a full 360° range with less than 3-dB power variation over 11.5-25 GHz. Besides, excellent long-term stability is presented with a maximum phase/power fluctuation of only 1.49°/0.57 dB. Compared with the conventional FD-OP-based photonic microwave phase shifter, the proposed one improves the second-order spurious free dynamic range (SFDR 2 ) by 13.57 dB.