Phase Shift Range Research Articles

A Compact Ka/Q Dual-Band GaAs MMIC Doherty Power Amplifier With Simplified Offset Lines for 5G Applications

In this paper, a Ka/Q dual-band Doherty power amplifier (DPA) with simplified offset lines is implemented in a 0.1-μm gallium arsenide (GaAs) process. It is found that the dual-band transmission lines (TLs) employed in the sub-6-GHz dual-band DPA are not suitable to be used as the offset lines in millimeter-wave (mm-wave) dual-band DPAs due to their large sizes and insert losses. An in-depth analysis reveals that the phase requirement of the offset lines can be relaxed, and the DPA exhibits a reasonable performance in a certain phase-shift range. A novel design method is proposed to realize offset lines using simple TLs, which can satisfy the phase-shift ranges in dual bands by choosing a proper electrical length. To enhance the gain of the DPA, a reversed uneven power splitter is adopted to deliver more power to the main power amplifier (PA). The fabricated DPA achieves an output power of 25.4/25.2 dBm, a peak power-added efficiency (PAE) of 33%/25%, and a 6-dB back-off PAE of 22%/17% at 29/46 GHz, respectively, with a compact size of 2.2 1.4 mm2. Applying a 20-MHZ 64-quadraticamplitude modulation (QAM) signal with a 7.7-dB peak-toaverage power ratio (PAPR), the measured average output power, PAE, and error vector magnitude (EVM) at 29/46 GHz are 18.4/19 dBm, 17%/15%, and 1.5%/1.1% after linearization, respectively. To the best of our knowledge, the proposed DPA is the first demonstration of mm-wave dual-band DPAs that do not require any additional switching or reconfiguration.

Wideband Tunable Differential Phase Shifter With Minimized In-Band Phase Deviation Error

This letter presents a tunable differential phase shifter with wideband flat phase characteristics. The proposed structure consists of a power dividing circuit and two 3-dB hybrids. To achieve the tunable flat phase characteristics over a wide bandwidth (BW), the coupled and through ports of one hybrid is terminated with short-circuited transmission lines (TLs), whereas those of another hybrid are terminated with a TL and varactor diode. For experimental validation, the proposed structure was designed and fabricated at a center frequency of 2.5 GHz. From the measurement results, the fabricated circuit provided a tunable differential phase shift range of 89° to 193° with a maximum in-band phase error of ±8.6° over a BW of 1 GHz.

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 (

A symmetric lattice‐based wideband wide phase range digital phase shifter topology

SummaryIn this paper, a novel digital phase shifter topology that achieves wideband and wide phase range is proposed. Wide frequency band operation is accomplished employing symmetrical all‐pass lattice structures. Compact phase shifter size is obtained utilizing the miniaturized microwave monolithic integrated circuit (MMIC) design implementation technology. Therefore, resulting phase shifter units are suitable for various communication systems such as radar and cellular communication smart antenna arrays. This paper provides complete design equations together with design algorithm for the selected phase shift and the center frequency. Design algorithm is developed on MatLab environment. The proposed phase shifting circuit is implemented employing the commercially available 0.18‐μm silicon CMOS technology. The new phase shifter topology provides 00 to 3600 phase shift range over X‐band, even beyond.

Design of Near-Field Focused Metasurface for High-Efficient Wireless Power Transfer With Multifocus Characteristics

This paper presents a new design of near-field focused metasurface for high-efficiency wireless power transfer with multifocus characteristics. A general synthesis procedure is outlined to design metasurfaces with desired multiple foci in the near-field zone. The unit cell of printed tridipole is used to realize the focused metasurface which has a large range of phase shift and is adapted to near-field focusing applications. Different feeding and focusing designs of the printed tridipole metasurfaces are proposed and analyzed. Two kinds of metasurfaces with 20×20 elements are designed, fabricated, and measured at 5.8 GHz. One is the single-feed and single-focus case, and the other is single-feed and two-focus case. Two-dimensional planar near-field scanning technique is implemented to measure the E -field focusing characteristics. Full-wave simulations and experiments demonstrate that the proposed focusing metasurfaces have a high wireless power transfer efficiency of 70%. The relative bandwidth with 50% power focusing efficiency is about 16%. The measured results are in good agreement with the theoretical designs and simulated results, which verify the feasibility and correctness of the proposed approach in this paper.

Wideband Filtering Phase Shifter Using Transversal Signal-Interference Techniques

A wideband filtering phase shifter is presented in this letter using transversal signal-interference techniques. The proposed structure creates two signal-propagation paths by introducing extra coupling between two short-ended stubs. Cascaded coupled-line sections and parallel short-ended stubs can generate a constant passband and multiple transmission zeros (TZs) in the stopband and meanwhile provide the arbitrary value of phase shift within the filtering band range. The positions of TZs and phase shift range can be easily controlled. Explicit relations between the objective filtering band and the related parameters are given, and cases with different in-band phase shift values are studied. To validate the design, a prototype is built, simulated, and tested using microstrip lines. The experimental results agree with the predicted ones, demonstrating that the device can realize any given in-band phase shift with a wideband filtering response.

A Double-Layer Wideband Transmitarray Antenna Using Two Degrees of Freedom Elements Around 20 GHz

A double-layer wideband transmitarray antenna using two degrees of freedom (TDF) elements is presented. The double-layer transmitarray antenna is composed of 441 elements. Each element includes four metal vias and two patches with TDF printed on both sides of the dielectric substrate. Four metal vias are used to achieve the maximum transmission magnitude and two patches with TDF are adopted to obtain a sufficiently large variation range of phase shift. A square transmittarray is designed, fabricated, and measured to validate the proposed design. The simulation and measurement results have a good agreement. The experimental results show that the proposed antenna has a high gain of 30.0 dBi at 21 GHz, aperture efficiency of 40% and 1 dB gain bandwidth of 9.6% (20.1–22.2 GHz). The proposed double-layer transmittarray antenna greatly simplifies the design complexity and reduces the thickness, mass, and cost with respect to existing transmitarray antennas.

Sub-3 Å apoferritin structure determined with full range of phase shifts using a single position of volta phase plate

Volta Phase Plate (VPP) has become an invaluable tool for cryo-EM structural determination of small protein complexes by increasing image contrast. Currently, the standard protocol of VPP usage periodically changes the VPP position to a fresh spot during data collection. Such a protocol was to target the phase shifts to a relatively narrow range (around 90°) based on the observations of increased phase shifts and image blur associated with more images taken with a single VPP position. Here, we report a 2.87 Å resolution structure of apoferritin reconstructed from a dataset collected using only a single position of VPP. The reconstruction resolution and map density features are nearly identical to the reconstruction from the control dataset collected with periodic change of VPP positions. Further experiments have verified that similar results, including a 2.5 Å resolution structure, could be obtained with a full range of phase shifts, different spots of variable phase shift increasing rates, and at different ages of the VPP post-installation. Furthermore, we have found that the phase shifts at low resolutions, probably related to the finite size of the Volta spots, could not be correctly modeled by current CTF model using a constant phase shift at all frequencies. In dataset III, severe beam tilt issue was identified but could be computationally corrected with iterative refinements. The observations in this study may provide new insights into further improvement of both the efficiency and robustness of VPP, and to help turn VPP into a plug-and-play device for high-resolution cryo-EM.

High-Efficiency Planar Reflectarray With Small-Size for OAM Generation at Microwave Range

In this letter, a high-efficiency planar reflectarray with a small size of 3.87λ0 × 3.87λ0 is designed, which can effectively convert arbitrary polarized waves to orbital angular momentum (OAM) waves with a desired mode number and a beam direction. The two concentric rings with a small size of 0.38 λ 0 × 0.38 λ 0 compose the unit, which can cover the phase-shifting range 360° by adjusting the ring radius. Though the developed reflectarray is much smaller than that of published ones, it can produce beams with the similar performance as large antennas. The advantages are as follows: high efficiency 22.6%, which is superior to published OAM reflectarrays, high gain 15.4 dBi, narrow divergence angle 9°, high purity, good stability, polarization insensitivity, planar structure, and easy fabrication. Using this reflective metasurface, we designed the following OAM beams: first, OAM mode l = 1, 2, 3, 4 at ( θ = 0°, ϕ = 0°); second, l = 1 at ( θ = 45°, ϕ = 180°); and third, l = 1 at ( θ = 45°, ϕ = 270°). The above advantages are proved by the following analysis: the magnitude and phase distributions in the near field, the purity analysis, and the radiation pattern in the far field.

Single-layer transmissive metasurface for generating OAM vortex wave with homogeneous radiation based on the principle of Fabry-Perot cavity

In this paper, a single-layer transmissive metasurface (TMS) is designed to generate orbital angular momentum (OAM) vortex waves with homogeneous radiation at microwave frequencies (e.g., 10 GHz). A single-layer TMS with the thickness of 3 mm (0.1λ0) is designed by well connecting the phase shift range of two elemental TMS structures. Specifically, two TMS structures—meandering patch-double meandering rings and meandering patch-single meandering ring with the unit-cell size of 7.5 mm (0.25λ0)—are used together to achieve high transmission efficiency (>0.8) and a large phase coverage range (>360°). In order to address issues such as uneven circumferential radiation and posterior lobe radiation and further enhance the efficiency of the TMS, the modified principle of Fabry-Perot cavity (FPc) suited for realizing the TMS to generate OAM vortex waves is proposed, analyzed closely, and applied. Specifically, an improved rectangular microstrip antenna is employed as a feeding source and a double square ring array is used to construct the backplane. A prototype of the proposed TMS with a FPc is designed, simulated, manufactured, and measured. The simulated and experimental results agree well, which demonstrate the feasibility of the presented design methodology.

X/Ku Dual-Band Single-Layer Reflectarray Antenna

In this letter, X/Ku dual-band single-layer reflectarray antenna is presented. The proposed reflectarray antenna operates in two separated bands with separate feeds. The reflectarray element is composed of a split ring with two phase delay lines and a phoenix patch. The split ring and phoenix patch are designed for operation at X- and Ku-bands, respectively. The split ring is selected as the lower frequency element because of the large enough internal space. The phase shift of these two elements does not depend on variation of external size, which provides a feasible method for designing dual-band elements. The lower band phase shift is obtained by changing the rotation angle of the phase delay lines. The movement of the inner loop of phoenix patch provides the required phase shift for the higher band. The proposed element realizes 360° phase shift range in both bands. The reflectarray is fabricated and measured to validate the design. The measured gains are 22.9 dBi at 8.5 GHz with aperture efficiency of 40%, and 28.8 dBi at 16 GHz with aperture efficiency of 44.8%. Besides, the 1 dB gain bandwidths are 20.5% (7.9–9.7 GHz) at lower band and 13.3% (14.7–16.8 GHz) at higher band.

A Double-Layer Highly Efficient and Wideband Transmitarray Antenna

A double-layer highly efficient and wideband transmitarray antenna is presented. The transmitarray element is composed of four metal vias and two crosspatches with two stubs. The metal vias penetrate the entire substrate and arrange symmetrically. The crosspatches are printed on both sides of the dielectric substrate. The metal vias are introduced to enhance the coupling strength. The stubs are added to ensure a sufficient phase shift range. The achievable transmission magnitude is greater than −2 dB, and the phase shift range exceeds 360° within the whole band. A transmitarray antenna using the proposed element was designed, manufactured, and measured. The simulation and measurement results are in good agreement. The measured maximum gain is 29.2 dBi at 18 GHz with the 51.4% aperture efficiency. The experimental results show that the proposed antenna has a 1-dB gain bandwidth of 9% (17.2–18.8 GHz). The proposed double-layer transmittarray antenna realizes the low-profile characteristic, simplifies the design complexity, and solves the problems of the mass and the cost.

A Balanced Phase Shifter With Common-Mode Suppression

In this paper, a balanced phase shifter using coupled line with loaded transmission line is proposed, which is the first balanced passive phase shifter providing both differential-mode (DM) phase shift and common-mode (CM) suppression simultaneously. Furthermore, the proposed design can provide (30°–90°) phase-shift range with characteristic of the wide bandwidth. Compared with single-ended phase shifters, the proposed design can be directly utilized in differential system without additional baluns. Compared with the state-of-arts balanced passive phase shifters, the proposed one shows the advantages of the CM suppression, wider bandwidth, wider alternative phase-shift range, and simpler structure. Three DM transmission poles can be obtained to support the wide bandwidth. Complete theoretical analysis and discussion are given to guide the design. To verify the theoretic prediction, three prototypes are designed with the operation bandwidth for 30° ± 2.5° (60° ± 4.2° and 90° ± 5.5°) of 68% (70% and 73%), with the minimum insertion of 0.2 dB (0.15 dB and 0.27 dB), with the CM suppression better than 10 dB, and with the minimum return loss of 17.8 dB (18.5 dB and 15.1 dB), respectively.

Angular Velocity and Phase Shift Control of Mechatronic Vibrational Setup

The paper is devoted to experimental study of possibilities for consensus control of the unbalanced rotors for the machine used in the vibration technology. This problem is treated as an ensuring the prescribed phase shift between the vibrating rotor actuators and has a significant value for the various kinds of the vibration technology, such as vibrating transportation, drilling, and so on. It can not be considered without taking into account the natural tendency of in-phase or anti-phase synchronization of the mechanically coupled oscillating units (cf. Huygens clock synchronization). This phenomenon prevents the controller efforts in maintaining the desired value of the phase shift. In the paper, the control laws for frequency stabilization simultaneously with cooperative control for assuring the desired phase shift between the rotors angular positions are derived and experimentally studied by means of the mechatronic vibration testbed. It is obtained that for the low and medium frequencies the self-synchronization of unbalanced rotors does not prevent achieving the desired phase shift between the rotors. For a high frequency band, the Huygens self-synchronization of rotors manifests itself, narrowing the range of the achievable phase shift.

Millimeter-Wave Thin Lens Using Multi-Patch Incorporated Unit Cells for Polarization-Dependent Beam Shaping

This paper describes a millimeter-wave thin lens that exhibits different beam-shaping characteristics depending on the polarization of the incident waves. The proposed unit cell topologies, which use multiple rectangular patches and rectangular-slotted grids, enable thinner (= 0.05λ 0 ) and smaller (= 0.168λ 0 ) features than in previous polarization-dependent lenses. An appropriate set of the proposed unit cells is shown to cover a tunable phase range of 180° with respect to one polarized wave but have an almost-zero tunable range of phase shifts with respect to another polarized wave. Thus, using this unit cell set for x-polarized incident waves, the proposed lens operates as a convex lens, whereas for y-polarized incident waves, the lens operates as a frequency selective surface. This confirms that gain variations of 13 dB or more can be differentiated according to the polarization of the incident waves on the lens, supporting polarization-dependent beam-shaping capability as a function of the polarization of incident waves.

Manipulation enhancement of terahertz liquid crystal phase shifter magnetically induced by ferromagnetic nanoparticles.

Ferromagnetic liquid crystals (FLCs), the suspensions of magnetic nanoparticles dispersed at different concentrations in liquid crystals (LCs), and their special magnetically induced birefringence characteristics have been investigated in the terahertz regime, mainly focusing on the interaction between magnetic cluster chains and LC molecules. We experimentally demonstrated the surface anchoring effect of the magnetic cluster chains on LC molecules in a mm-thick LC cell under an extremely weak external magnetic field (EMF), leading to a uniform anchoring arrangement of the LC molecules over the entire LC cell. Unlike pure 5CB LCs, the phase shift range of the FLCs at 1.45 THz up to π (no to ne or ne to no) can be achieved over the whole tunable range by simply changing the magnitude of the EMF without changing its direction, and the optical axis of LC molecules can be controlled to rotate by 90°, thereby realizing a tunable THz wave plate. This work provides a new way in the development of THz magneto-optic devices and phase devices.

In‐band phase deviation minimization method for wideband tunable phase shifter

AbstractThis article provides a novel approach to analyze and design wideband tunable reflection‐type phase shifter (RTPS) with low in‐band phase deviation (IBPD) error. The proposed RTPS consists of coupled lines where through and coupled ports are terminated with varactor diodes. The coupled lines can minimize the parasitic elements of varactor diode to achieve high phase shift range (PSR). In addition, the measured frequency‐dependent capacitance of varactor diode was used in the analytical analysis to obtain minimum IBPD error and high PSR. For experimental demonstration, phase shifter was fabricated at the center frequency of 2.5 GHz. The measured results show that the fabricated circuit achieved 126.85° PSR with ±6.48° IBPD error for 500 MHz bandwidth (BW). In addition, the measured maximum insertion loss variation and input/output return losses are within ±0.34 dB and higher than 16.85 dB within 500 MHz BW, respectively.

Tunable Silicon Photonic RF Phase Shifter With Low RF Power Variation Based on Constructive Interference of an Add-Drop Ring Resonator

We propose and experimentally demonstrate a tunable silicon photonic radio frequency (RF) phase shifter with low power variation based on constructive interference of an add-drop ring resonator. The thermal nonlinear effect of the add-drop ring resonator is used to realize a nearly 2π-phase shift, and the RF power variation is minimized by allowing two lights at the outputs of the add-drop ring resonator to combine at a directional coupler to achieve constructive interference. By thermally tuning the add-drop ring resonator, a nearly 2π-phase shift is realized and the operation is verified by an experiment. Experimental results show that a 0-5.2-rad phase-shift range with an RF power variation within 0.2 dB for a frequency range of a 40-GHz signal is achieved by thermally tuning the ring resonator. A phase shift up to 4.1 rad over a frequency range of 20-40 GHz is also realized.

Reconfigurable Impedance Matching Networks With Controllable Phase Shift

Two kinds of reconfigurable impedance matching networks with controllable phase shift are proposed. The reconfigurable networks can match different loads with desired phase shift at center frequency and no extra phase shifter is needed. The two networks are realized by using varactor diodes and switches, respectively. The design equations and achievable phase shift range of the two networks are derived. Two prototypes working at 1 GHz were fabricated for verification. The measured results show good return loss response and precise phase shift value.

A 60-GHz Transmission Line Phase Shifter Using Varactors and Tunable Inductors in 65-nm CMOS Technology

This paper describes a 60-GHz artificial transmission line phase shifter designed in 65-nm CMOS technology. To increase the phase shift range and preserve the matching over the entire phase shift range, the fixed series inductors in the standard line cell are substituted by tunable inductors. The required tunable inductors are constructed using a transformer with the transformer secondary loaded by a varactor. To verify the operation principle, the phase shifters, including one-, two- and three-cell, are manufactured. The experimental phase shift range is 45° for one-cell, 92° for two-cell, and 133° for three-cell line shifters. These figures are nearly 80% larger than the corresponding phase shifts in the lines consisting of cells with fixed inductors. The input/output return loss is less than 10 dB for all cases over the entire phase shift range. The average insertion loss is 3.2 dB for one-cell, 5.6 dB for two-cell, and 7.8 dB for three-cell transmission line phase shifters. The proposed continuous phase shifter achieves the highest phase shift range per area among the millimeter-wave transmission line and switch-type phase shifters reported to date.