Balanced Phase Shifter Research Articles

A tunable balanced phase shifter with wide operating bandwidth

Abstract A wideband tunable balanced phase shifter is achieved by utilizing varactor-loaded coupled lines (VLCLs)-embedded multistage branch-line structure. The tunable phase shift with low in-band phase deviation is attributed to the regulation in phase shift of the VLCLs and the horizontal microstrip lines in series. The wideband differential-mode (DM) impedance matching and common-mode (CM) suppression are due to multiple DM transmission poles and CM transmission zeros, which are brought about by the cascade of VLCLs and a microstrip line with short-circuited stubs in the DM-equivalent circuit and open-circuited stubs in the CM-equivalent circuit, respectively. Compared with the state-of-the-art tunable balanced phase shifters, the proposed design not only has the advantages of wide operating bandwidth (BW) with low in-band phase deviation but also has low insertion loss and easily fabricated structure. Theoretical analysis and design procedure were conducted, resulting in a prototype covering the frequency of 1.8 GHz. This prototype offers a tunable phase shift capability ranging from 0° to 90°. The prototype exhibits an operating BW of 45%, with a maximum phase deviation of ±6°. It also achieves a 10 dB DM return loss and CM suppression, while maintaining a maximum insertion loss of 2.5 dB.

A Balanced Substrate Integrated Waveguide Phase Shifter with Wideband Common-Mode Suppression

In this paper, a slotted substrate integrated waveguide (SIW) is used to create a balanced phase shifter with wideband common-mode (CM) suppression. Differential-mode (DM) impedance matching and CM suppression are achieved by utilizing the fact that TE20 mode and TE10 (TE30) mode can only transmit DM signals and CM signals, respectively, and by increasing the bandwidth for CM suppression via slots. Furthermore, a wideband phase shift with low phase deviation can be obtained due to the phase slop counteract between the slot and the delay line. Compared with the state-of-the-art, the proposed one has the advantages of wideband CM suppression, wide phase shift range, and a simple and easy-to-make structure. Five prototypes covering the frequency of 3.5 GHz are designed with the relative operating bandwidth for 45° ± 2° (90° ± 4.5°, 135° ± 6°, and 180° ± 8°) phase shifter of 20% (20%, 20%, and 20%), with the minimum insertion loss of 0.41 dB (0.5 dB, 0.58 dB, and 0.59 dB), with the minimum return loss greater than 15 dB, and with the relative bandwidth for 15-dB CM suppression of 59% (59%, 58%, and 57%).

Balanced Wideband Quasi-Schiffman Phase Shifters Based on Slotlines

This brief presents a quasi-design about balanced wideband Schiffman phase shifters based on slotlines, which can achieve phase shift with relatively small phase equiripple and high common mode (CM) rejection. The proposed balanced phase shifters are mainly composed of a microstrip/slotline transition structure and a C-section coupling slotline. C-section coupling slotline consisting of two long parallel coupling slotlines and two short parallel coupling slotline can achieve the phase shift function. The microstrip/slotline transition structure is employed as a balanced port, so that the differential mode (DM) response and CM one are independent of each other. Different from the traditional Schiffman phase shifter: two methods are used to compensate the different phase velocity between the odd and even modes. In order to decrease the DM transmission loss, sandwich structure is also employed in this design. To the best of authors’ knowledge, the balanced wideband Schiffman phase shifter based on slotline may be the first ever reported. Finally, 45°, 90° and 180° phase shifters with a central frequency at 2.37 GHz are achieved to verify the design method. The measured results agree well with the simulation.

A reconfigurable balanced loaded‐line phase shifter based on slot line

A reconfigurable balanced phase shifter is designed in this paper, which can achieve stable differential mode (DM) phase shift and high common mode (CM) suppression. The proposed balanced phase shifter is mainly composed of micro strip/slot line transition structure and π-shape slot line. The U-shaped micro strip line and the stepped impedance slot line are employed to form the differential input and output ports, which can make the DM response and the CM one are independent. By switching the PIN diode on or off, a stable 180° DM phase shift difference is achieved between two states. In order to verify the design, a 180° balanced phase shifter with a central frequency of 4.7 GHz was simulated and fabricated. DM insertion loss of the design is 1.1 dB, DM phase deviation range is ±5°, 10 dB DM impedance matching fractional bandwidth is 45%, and phase fractional deviation bandwidth is 42%. Meanwhile, the CM rejection can reach about 35 dB. The simulation and measurement are in good agreement with the theory.

Compact behavioral model and parametric extraction for optical phase shifters in carrier-depletion Mach–Zehnder silicon modulators

Testing of active photonic devices is totally different from testing of pure electronics; in particular, reduction of testing time in silicon photonics has been a significant issue. In this study, a compact behavioral model of optical phase shifters is constructed for carrier-depletion Mach–Zehnder (MZ) silicon modulators in the push–pull regime. The target characteristics, i.e., the dynamic extinction ratio (ER), absorption loss, and chirp parameter, are expressed in simple forms in terms of parameters representing the voltages-dependent modulation efficiency (ME) and the imaginary part of the effective index. The parameters reflecting manufacturing variability can be quickly extracted from fast DC measurements, which shortens the testing time. The theoretical concept relies on the proposal of a generalized form of the large-signal ME and an effective approximation for model construction that avoids the problem of the conventional small-signal definition being not applicable and large-signal definition leading to a cumbersome and non-intuitive formulation. It is shown that the constructed model suitably explains the physics and the reported experimental results for the slightly positive chirp characteristics of balanced phase shifters. Moreover, a parametric extraction applying the model is demonstrated in the C-band wavelength on a 300-mm SOI wafer.

Simple ladder‐like single‐layer balanced wideband phase shifter with wide phase shift range and appropriate common‐mode suppression

In this study, a single-layer balanced wideband phase shifter with a wide phase shift range of 45°–315° and acceptable common-mode (CM) suppression is proposed. The main branch has a simple ladder-like structure and the reference branch utilises a coupling structure. The main branch electrical length is constant for any desired differential-mode (DM) phase shift. Assuming a specific return loss (e.g. 16, 20, and 25 dB), the phase shifter is carefully analysed and a design procedure is given leading to an ultra-low phase error design. Then by making a trade-off between the CM and DM bandwidths at the cost of higher phase error, more design solutions for the phase shifter are given. To validate both the proposed structure as well as its design procedure, a balanced wideband phase shifter with the DM phase shift of 180°±4.2° (1.851–4.017 GHz) and the CM suppression of better than 15 dB (1.81–4 GHz) is fabricated, resulting in 73.82 and 75.25% fractional bandwidth, respectively. The fabricated balanced phase shifter has a return loss of and insertion loss of . The synthesised, simulated, and measured results are in good agreement with each other.

Tunable balanced liquid crystal phase shifter based on spoof surface plasmon polaritons with common-mode suppression

ABSTRACT In this paper, a novel design approach for microwave tunable balanced phase shifters with the common-mode (CM) suppression is proposed based on the liquid crystal (LC) technology. The proposed tunable balanced liquid crystal phase shifter (LCPS) is designed by the LC-based microstrip differential line with periodical T-shaped stubs, which supports the spoof surface plasmon polaritons (SSPP) mode. Thanks to the slow-wave characteristic induced by the SSPP mode, both tunable phase shifts and figure of merit (FoM) of the balanced LCPS are effectively enhanced. In addition, the defected ground structure based on slotted dumbbell-shaped resonators is also employed in this design and the CM suppression is integrated into tunable balanced phase shifters for the first time. Finally, the corresponding prototype is fabricated and tested to verify the above theoretical analysis. The measured results demonstrate that this proposed tunable balanced LCPS can simultaneously achieve tunable phase shifts with FoM of more than 12.4°/dB and the CM noise suppression of more than 17 dB attenuation from 2.5 to 5.5 GHz.

A Compact Single-Layer Balanced Phase Shifter With Wide Bandwidth and Uniform Reference Line

A Compact Single-Layer Balanced Phase Shifter With Wide Bandwidth and Uniform Reference Line

Balanced Wideband Phase Shifters With Wide Phase Shift Range and Good Common-Mode Suppression

This paper proposes a class of balanced wideband phase shifters with wide phase shift range and good common-mode (CM) suppression. Both the balanced filtering units in the reference and main branches consist of horizontal half-wavelength branches and vertical quarter-wavelength loaded stubs but with dissimilar sizes. The differential-mode (DM) section of these two units can achieve ( $2N + 1$ )th-order Chebyshev amplitude response while with discrepant phase characteristics, which can be utilized in the design of balanced phase shifters with large phase shift. As another interesting feature, the proposed balanced filtering unit functions as the conventional branch-line bandstop response in CM, and its frequency selectivity can be further enhanced by using the so-called signal-interference method. The proposed balanced wideband phase shifters have the advantages of wide phase shift range, low phase deviation, high level and wide range for CM rejection in both two branches. The 30°, 60°, 90°, 120°, 150°, and 180° balanced phase shifters are then studied and designed. As the typical examples, 30°, 90°, and 180° phase shifters are designed, fabricated, and measured. The 30° and 90° phase shifters have a fifth-order Chebyshev response, while the 180° phase shifter is of fifth-order and third-order Chebyshev responses in the reference and main branches, respectively. The measured results show that the phase shift values are 30.14° ± 2.2°, 90.75° ± 4.05°, and 180.1° ± 5.5°, the phase shift bandwidths are 73%, 68.5%, and 66.8%, and the CM rejections are −23.3, −22, and −14.6 dB, respectively.

Balanced Wideband Phase Shifters With Good Filtering Property and Common-Mode Suppression

In this paper, a class of balanced wideband phase shifters with good filtering property and common-mode (CM) suppression is proposed, synthetically designed, and implemented. Unlike the conventional coupled-line reference branch one, the proposed balanced phase shifter has its T-shaped structure in both of main and reference branches, so as to achieve superior passband selectivity and CM rejection simultaneously. The synthesis method is then presented to design the proposed balanced wideband phase shifters with the prescribed phase shift value, passband ripple, maximum phase deviation, and fabricated bandwidth. The 30°, 45°, 60°, 75°, and 90° balanced phase shifters are theoretically designed and demonstrated. To validate the design method, two prototypes with different fractional bandwidths (FBWs) and phase shift values (Case 1: FBW = 66.7%, typical phase shift value is 30°; Case 2: FBW = 55.6%, typical phase shift value is 90°) are designed, fabricated, and measured. The synthesized, simulated, and measured results are found in good agreement with each other.

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.

A Compact Balanced Phase Shifter With Wideband Common-Mode Suppression

In this paper, a balanced phase shifter using cascaded three microstirp lines and two coupled lines is proposed. The reference line is fixed without center delay line. With such configuration, wideband differential-mode (DM) phase shift can be achieved. The coupled line and half-wavelength microstrip line provide the out-of-band and in-band common-mode (CM) suppression, respectively. Compared with the state-of-the-art balanced phase shifters, the proposed balanced phase shifter has the advantages of wideband CM suppression and compact size with simple structure and fixed reference line. Theoretic analysis, parametric study and design procedure are carried out completely. To verify the theoretic prediction, two prototypes covering the frequency of 1.8 GHz are designed with the relative operating bandwidth for 45° ± 2.1° (90° ± 3.7°) phase shifter of 50% (53%), with the minimum return loss better than 14.7 dB, and the relative CM suppression bandwidth better than 150%.

K‐band 0/180° balanced phase shifter with dc‐offset cancellation

K-band 0°/180° phase shifter MMIC based on balanced structure which can be applied to BPSK or QPSK modulator with dc-offset cancellation is presented. The proposed balanced phase shifter consists of four Lange couplers, two quarter-wave transmission lines and four switches for open and short terminations. The proposed structure implemented in GaAs 0.15-µm low noise pHEMT process ensures stable 0/180° phase shift while common-mode signals due to the mismatch in reflections by open and short are fed to the isolation port. The proposed phase shifter is verified by the phase shift of 179 ± 1.5° with the insertion loss of 4.5 ± 0.8 dB from 17.5 to 22.5 GHz. The fabricated phase shifter size is 2.2 × 2.85 mm including test pads.

A Balanced Digital Phase Shifter by a Novel Switching-Mode Topology

A balanced digital phase shifter by a novel switching-mode topology is proposed. A 3-bit balanced digital phase shifter is given as an example, the working bandwidth of which is from 2.3 to 2.7 GHz. The proposed 3-bit balanced phase shifter comprises two balanced loaded-line phase shifters (90° and 45°) and six twist-line broadband 180° phase shifters. The balanced loaded-line digital phase shifter changes phases while the even- or odd-mode signal is excited. The 180° phase shifter controls the balanced signal to be even or odd mode. The commensurate transmission line filter is used as the biasing circuit.

単相により制御されるサイリスタゲート用多相平衡移相器の解析

単相により制御されるサイリスタゲート用多相平衡移相器の解析

Magnetic balanced phase shifter for polyphase supply

A novel method of balanced firing of thyristors used for polyphase supply is presented. The phase angles of the polyphase voltages are shifted simultaneously by controlling a phase shifter of a single phase. A simple feedback circuit including a saturable core and an integrator plays a key role in this balanced phase shifter. Phase distortions due to the change of the supply voltage and of the supply frequency can be almost completely removed by this new method.