Quadrature Phase Shifter Research Articles

Design of a Broadband Comparator Network at $X$-Band

This paper presents a novel broadband comparator network design operating at X-band. A multilayer aperture coupling scheme and shielding around the microstrip structures are utilized to achieve broadband performance. There are two main building blocks of the proposed comparator network. These are a quadrature hybrid coupler and a 90-degree phase shifter. These two main components are designed to have broadband performance so that the designed comparator would also have wideband performance. The proposed quadrature hybrid coupler achieves more than 19.7 dB return loss, a 0.75 dB amplitude imbalance, and 1.4 ° phase imbalance along the frequency band 5 GHz to 10 GHz. The 90-deg. phase shifter has less than -10 dB S11 in addition to having less than 1.6 °. phase error and 1.5 dB insertion loss within the frequency band 5 GHz to 9.9 GHz. The proposed comparator is acquired by combining the multiple quadrature hybrid couplers and phase shifters. The results of the manufactured and simulated comparator agree well with each other. The impedance bandwidth (VSWR<2) of the manufactured comparator is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> 61 and operates from 5.26 GHz to 9.9 GHz. An 8x8 microstrip patch antenna array is designed and manufactured to verify the comparator network's sum and diff pattern forming capability. The far-field measurements of the proposed comparator combined with the 8x8 antenna array indicate that 36 dB null depth is acquired at the azimuth plane, and 40 dB null depth is achieved at the elevation plane.

Quadrature phase shifter for the measurement systems of testing of electrical insulation

Quadrature phase shifters are widely used in practice of development of measurement systems intended for the measurements of dielectric dissipation factor and electrical capacitance. This article presents the examples of implementation of phase shifters intended to obtain the value of phase shift equal to 90º for the applying in measurement systems of monitoring and diagnosing the technical condition of electrical insulation. The developed solutions are based on applying of the analog signal multiplier implemented in the AD633 integrated circuit. The required value of phase shift is provided by adding a pre-shifted at a certain angle input harmonic signal to a signal with the reduced amplitude and the opposite initial phase. The article is also focused on the development of schematic solutions which can be used in order to remove the undesirable for many practical applications discrepancy between the amplitudes of the input and the output signals. This alignment of amplitudes is provided by the detection of their average rectified values with subsequent multiplication of their ratio by the shifted at 90º signal with the reduced amplitude. The designed schematic solutions imply the applying of analog circuits which contain the input phase shifter, low pass filter, voltage summing amplifier, two detectors of average rectified values, three analog multipliers and one voltage divider.

Overview of methods and means of implementation of information and measuring components cyber-physical systems for electromagnetic probing

The object of research is cyber-physical systems for the study of inhomogeneous environments, in particular, such as land and water depths, in order to find in them the leading bodies. One of the most problematic places in the creation of such systems is a highly sensitive meter of small phase shifts with a low sensitivity threshold. During the study, a review of methods for achieving a low threshold of sensitivity to phase shift. The main one is the method of converting the phase shift into the amplitude modulation coefficient. The implementation of the method is based on the sum-difference transformation with the preliminary introduction of the quadrature phase shift between the signals. The results concerning the methods of solving the following problems are obtained: – increasing the temperature stability of the quadrature phase shifter; – reducing the non-identity of the transmission coefficients of the sumo-difference scheme channels; – allocation of the amplitude of the amplitude-phase-modulated signal at low ratios of the frequencies of the input signals and switching. The first problem is partially solved by dividing the quadrature phase shifter into two equal halves, placed in different channels, with approximately the same phase temperature coefficients. The second problem is also solved by manual calibration before measurement. The most difficult task is to extract the bypass from the amplitude-phase-modulated signal, in which the carrier frequency is only several times greater than the bypass. The difficulty is that the detection produces combinational frequencies due to phase modulation. Therefore, it is difficult to separate them. Several methods of allocating the bypass, if the frequency of the input signals is fixed, are considered. This allows to get the sensitivity threshold(1·10–4÷3·10–5) of advice. Reducing the operating frequency of the signals increases the depth of research, but increases the impact of flicker noise. The minimum frequency is 10 Hz. Therefore, these methods are not suitable for frequencies of Hz units. Methods to reduce the impact of flicker noise will be considered in another paper.

Robust Analog Multi-Sensory Array System for Lossy Capacitive Sensors Over Long Distances

A robust capacitive multi-sensory readout system is presented in this paper. The system consists of a few thousand lossy capacitive-based sensors which can be modeled as a parallel connection of sensor capacitor and undesirable leakage resistance. The real system in our application will consist of a high number of capacitive sensors used for the monitoring of relative humidity in a High Energy detector at CERN. However, our findings apply to any set of capacitive devices aimed to any other sensing application. Furthermore, the proposed system is intended for harsh environments (e.g. with high radiation levels and magnetic field presence) where the readout system is separated from the sensor and placed far away, connecting to them via cables. In such cases, the presence of cables brings another issue to the readout system – parasitic capacitance. Using long cables, we introduce high values of parasitic capacitance that make the sensor capacitance practically invisible to the readout unit. This paper presents an effective, robust, analog method, based on a quadrature-phase shifter and an auto-balancing bridge, used to overcome the sensor leakage resistance and parasitic capacitance caused by the cables. The experiments for various values of capacitance and leakage resistance at different frequencies and the influence of different cable lengths and types are analyzed and discussed.

An accurate digital converter for lossy capacitive sensors

This paper presents an incremental delta-sigma based capacitance-to-digital converter for lossy capacitive sensors. The proposed converter consists of a capacitance-to-voltage converter followed by a single-bit incremental delta-sigma converter. Unlike conventional incremental-delta sigma converter where a fixed reference voltage signal is utilized, the proposed converter utilizes a reference signal which depends on the amplitude and frequency of the input excitation signal. The generated reference signal for the incremental-delta sigma converter reduces the error in the capacitance measurement due to variation in the excitation signal frequency and amplitude. In addition, the proposed converter utilizes a frequency-independent quadrature phase shifter circuit for the generation of reference π/2 phase-shifted signal for the phase-sensitive detection operation. Moreover, a modified clock counting approach is utilized to measure the sensor capacitance accurately. A prototype of the proposed circuit is fabricated using commercial off-the-shelf components and tested. The experimental results demonstrate that the circuit is able to measure the sensor capacitor in the range from 20 pF to 163 pF. The worst-case error in sensor capacitance measurement was less than 0.2%. Furthermore, the proposed converter experimentally provides a signal-to-noise ratio of 56.66 dB.

A 170 MHz to 330 MHz Wideband 90 nm CMOS RC–CR Phase Shifter with Integrated On-Line Amplitude Locked Loop Calibration for Hartley Image Rejection Transceiver

A 160 MHz bandwidth 90° active RC–CR phase shifter with integrated on-line amplitude locked loop (ALL) calibration targeted to 802.11ac 5 GHz wireless local area network (WLAN) applications is presented in this paper. The quadrature phase shifter is a key component for transceivers employing the Hartley image rejection architecture. The passive RC–CR phase shifter generates the required two quadrature outputs with an accurate 90° phase shift over the required bandwidth but lack the required accuracy in amplitude matching. A 90 nm CMOS microelectronic implementation of an RC–CR phase shifter is proposed with active resistors that are adjusted by an integrated on-line ALL calibration system to maintain matching amplitudes of the quadrature outputs over the required bandwidth. The on-line ALL calibration system employs peak detectors, comparators, digital logic control, and charge pump to incrementally adjust the active resistors while converging to matched amplitudes similar to the operation of phase-locked loop with a phase-frequency detector and charge pump. The resulting 90 nm implementation supports − 40db to − 70db image rejection ratios (IMMRs) over the IF 170 MHz to 330 MHz bandwidth. The 90 nm CMOS implementation is fully functional considering process variations based on 200 Monte Carlo simulations.

Multiplexed Cassegrain Reflector Antenna for Simultaneous Generation of Three Orbital Angular Momentum (OAM) Modes.

A multiplexed Cassegrain reflector antenna with a 2 × 2 open-ended rectangular waveguide (OERW) matrix feed and an orbital angular momentum (OAM) mode mux is proposed for the simultaneous generation of three OAM modes (l = 0, ±1). The OAM mode mux (OMM) was designed using sequential combinations of quadrature hybrids, crossovers, and phase shifters to multiplex and demultiplex three OAM modes at the same time. The 2 × 2 OERW matrix feed and the OMM were separately measured and their performances were verified according to proposed theories. A near-field antenna measurement for a multiplexed Cassegrain reflector antenna was conducted to obtain the far-field magnitude and phase patterns around polar elevation angle θ and azimuthal angle ϕ, thus confirming that our antenna can produce three OAM modes simultaneously. We also measured the communication link characteristics of two identical multiplexed antennas. The measurement results show that the channel isolation of three OAM modes is more than 12.7 [dB] and 17 [dB] for fixed and compensated receiver positions, respectively, indicating that the proposed antenna system can be used for independent communication links with the same frequency and polarisation.

A WCDMA/WLAN Digital Polar Transmitter With Low-Noise ADPLL, Wideband PM/AM Modulator, and Linearized PA

This paper presents a single-chip digital-intensive polar transmitter for WCDMA and WLAN integrating a low-phase-noise all-digital phase-locked loop (ADPLL), a digitally-controlled wideband phase/amplitude modulator, and a calibration-free high-linearity power amplifier. From the ADPLL, the 1.7–2.5 GHz LO signal is generated together with a ${\div} $ 1.5 frequency divider to eliminate DCO pulling. The phase noise of the ADPLL is optimized by using a linearized stochastic TDC with 3 ps resolution and a Class-C quadrature DCO (QDCO) with embedded quadrature phase shifter and quantization-noise filter. A 2-segment $\Sigma \Delta$ switching phase modulator enhances the PM bandwidth up to 200 MHz, and a digital polar amplifier employs AM-replica linearization to eliminate AM pre-distortion. The TX achieves a ${-}$ 1 dB output compression point of 22.8 dBm with an overall system efficiency of 27.6% and measures EVM of 4% for a 20 MHz 64-QAM signal at an output power of 13.8 dBm.

Design and Analysis of a Wideband 15–35-GHz Quadrature Phase Shifter With Inductive Loading

A Ku-, K-, and Ka-band phase shifter for beamforming applications is presented in this paper. An analysis showing the effect of loading conditions on quadrature phase accuracy in a simple poly-phase filter is carried out. Based on the analysis, a novel quadrature phase shifter (QPS) with inductive load is proposed. Sign-selection and vector addition is performed in two stages to lower supply voltage. The proposed phase shifter is fabricated in a 0.18- μm SiGe BiCMOS process and occupies an area of 520 μm×370 μm. The proposed QPS has a maximum phase error of 6.38 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> over 15-35 GHz while maintaining an amplitude imbalance less than 2 dB. When combined into a 4-bit phase shifter, the root mean square (rms) gain error is less than 2.2 dB and the rms phase error is less than 13 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> over 15-35 GHz. The phase shifter thus achieves a full 360 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> phase-shift range with 22.5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> phase resolution. The total power consumption is 14 mA from a 1.8-V power supply. The phase shifter achieves an input P1dB of -6.25 dBm. The measured phase-shifting fractional bandwidth of 87% is the highest reported thus far in the literature for SiGe BiCMOS implementation.

A V-Band 8$\,\times\,$8 CMOS Butler Matrix MMIC

This paper presents a fully integrated V-band 8 x 8 Butler matrix in 0.13-μm CMOS technology. Since the number of building blocks exponentially increases with the order of the Butler matrix, the constituted components, including quadrature hybrids, phase shifters, and crossovers, must be redesigned for single-chip implementation in silicon. Design equations and novel layout arrangements are described. A demonstrated 8 x 8 Butler matrix was implemented, which has the compact chip size of 1.45 x 0.93 mm2, no dc power consumption, and low average loss of 3.1 dB. Eight spatial beams with the averaged 5.9 dBi gain and 0.6° main-beam direction tolerance were obtained in 56 to 66 GHz.

Novel Design of a 2.5-GHz Fully Integrated CMOS Butler Matrix for Smart-Antenna Systems

This paper presents a novel design of monolithic 2.5-GHz 4times4 Butler matrix in 0.18-mum CMOS technology. To achieve a full integration of smart antenna system monolithically, the proposed Butler matrix is designed with the phase-compensated transformer-based quadrature couplers and reflection-type phase shifters. The measurements show an accurate phase distribution of 45plusmn3deg, 135 plusmn 4deg, -45 plusmn 3deg, and -135 plusmn 4deg with amplitude imbalance less than 1.5 dB. The antenna beamforming capability is also demonstrated by integrating the Butler matrix with a 1 X 4 monopole antenna array. The generated beams are pointing to -45deg, -15deg, 15deg, and 45deg, respectively, with less than 1deg error, which agree very well with the predictions. This Butler matrix consumes no dc power and only occupies the chip area of 1.36 times 1.47 mm2. To our knowledge, this is the first demonstration of the single-chip Butler matrix in CMOS technology.

Application of metamaterial transmission lines to design of quadrature phase shifters

It is demonstrated that metamaterial transmission lines based on complementary split rings resonators (CSRRs) can be applied to the design of quadrature phase shifters with compact dimensions and broad operational bandwidth. The structure consists of a Y-junction with output lines exhibiting a phase difference of 90°, these lines being artificial and implemented by means of CSRRs. The device is compared to a conventional implementation. From the characterisation of both devices it is concluded that the phase difference is preserved over a wider band in the metamaterial-based phase shifter.

A high performance frequency insensitive quadrature phase shifter and its application in reactive power measurements

This paper describes a high precision circuit for quadrature phase shifting in which frequency controlled signal amplification is introduced so that the amplitude of the phase shifted signal is not dependent on the frequency of the input signal. The proposed quadrature phase shifting method is aimed at high accuracy reactive power measurements in ac power systems. The implementation of the new phase shifter at the voltage input of a watt/watt hour meter allows for high accuracy var/varh measurements. A prototype of the quadrature phase shifter has been built with magnitude and phase errors within /spl plusmn/15/spl middot/10/sup -6/ and less than 40 /spl mu/rad, respectively. Its performance was further confirmed when the QPS was used for reactive power measurements.

A high-power PWM quadrature booster phase shifter based on a multimodule AC controller

Pulse-width-modulated (PWM) phase shifters allow the smooth control of power flow in a transmission line. This paper analyzes a PWM quadrature booster phase shifter based on a multimodule AC controller structure to attain high voltage levels and improve the harmonic spectrum. The modules are based on a three-phase PWM AC controller topology that employs only four force-commutated switches and is controlled by duty-cycle variation. The PWM technique is carrier based and the individual modules are gated through phase-shifted triangular carriers. As a result, harmonic cancellation takes place in the input current and output voltage. Low-order harmonics are therefore eliminated and the amplitude of remaining components reduced. An additional operating mode with negligible harmonic generation and step-like control is identified. The feasibility and advantages of the proposed phase shifter are demonstrated by means of a power system simulator.

Calculation of tightly coupled transmission lines for MMIC/MHMIC technology

Analyses and calculations are performed to provide design equations for new tightly coupled transmission lines, compatible with MMIC/MHMIC technology . In this design, short subsections of different lines loaded by MIM capacitors are connected together to achieve the tight coupling needed. The design equations obtained are in good agreement with previous computer simulation results and experiments and will facilitate the design of the above transmission line to realise wideband quadrature couplers and Schiffman phase shifters.

Quadrature phase shifter for audio frequency sinewaves

A quadrature phase shifter for sinusoidal signals is presented. The circuit provides phase delay (within ) and unity gain (within 6%) in the frequency range 100 Hz to 10 kHz. It consists of a second-order lowpass current-controlled filter; the cutoff frequency is mantained equal to the input frequency with a frequency to current converter. In this way, the filter provides a phase delay between input and output. The main feature of the phase shifter is the absence of internal feedback; this avoids the introduction of long settling time constants when the phase shifter is part of control loops and gives almost instantaneous (within a period) resettling of the phase delay when amplitude or phase variations of the input signal occur.

A 1.9-GHz-band GaAs direct-quadrature modulator IC with a phase shifter

A 1.9-GHz-band direct-quadrature modulator IC has been successfully developed for digital portable telephone use. In the 1.9-GHz high-frequency band, both image and carrier rejections as low as -40 dBc have been obtained with a low-power dissipation of 110 mW at a single power supply of 3.1 V, corresponding to a phase error below 1.1. In order to reduce undesired sideband spectral components required for digital modulation, a newly developed circuit configuration that combines a quadrature phase shifter with drivers for amplitude imbalance compensation and makes spectrum efficiency and low-power dissipation possible is used. The modulator IC may be used in enhanced digital mobile radiocommunication systems such as digital portable telephones.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A multioctave active GaAs MMIC quadrature phase shifter

A GaAs monolithic quadrature phase shifter based on a phase-locked-loop system which covers a 0.1- to 4.5-GHz frequency range is presented. It provides about 8 dB of gain, and its phase error and amplitude mismatch are respectively, less than 2.5 degrees and 0.4 dB over the band. When the phase shifter is integrated into a single-sideband receiver, a sideband rejection of at least 30 dB is achieved. The results also show that design methods based on voltage amplification instead of power amplification, without any impedance matching between stages, can be extended up to the microwave domain.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Phase Shifts in Single- and Dual-Gate GaAs MESFET's for 2-4-GHz Quadrature Phase Shifters (Comments)

Phase Shifts in Single- and Dual-Gate GaAs MESFET's for 2-4-GHz Quadrature Phase Shifters (Comments)

Phase Shifts in Single- and Dual-Gate GaAs MESFET's for 2-4-GHz Quadrature Phase Shifters

The variation of transmission phase for single- and dual-gate GaAs MESFET's with bias change and its probable effects on the performance of an active phase shifter have been studied for the frequency range 2 to 4 GHz. from measured S-parameter values for single- and dual-gate transistors, the element values of the equivalent circuits were fitted by using the computer-aided design program SUPER COMPACT. For the normal full-gate voltage range 0 to -2 V at V/sub DS/= 4 V, the single-gate MESFET varies in transmission phase from 142° to 149° at 2 GHz, and from 109° to 119° at 4 GHz. However, with drain voltage varied from 0.3 to 4 V and a constant gate-voltage bias of 0 V, the phase shifts are much larger, 105° to 145° at 2 GHz and 78° to 112° at 4 GHz. this suggests that large phase shifts may be expected in a dual-gate device and this is found to be so. With V/sub DS/= 4 Vand V/sub GS1/= - 1.0 V, variation of control (second) gate bias from 0 to - 1.75 V for the NE463 GaAs MESFET produces a transmission phase variation from 95° to 132° at 2 GHz and 41° to 88° at 4 GHz. Such phase shifts cause both amplitude and phase errors in phase-shifter circuits of the kind where signals from two FET channels are combined in quadrature with their gate voltages controlled to provide 0° to 90° phase control with constant amplitude. For the single-gate FET examined, the expected amplitude and phase errors are 0.30 dB and 6° at 2 GHz, and 0.36 dB and 10° at 4 GHz. If dual-gate FET's are used in similar circuits, the distribution of errors is different. For NE463 devices, the corresponding figures are 0.56 dB and 2° at 2 GHz and 1.2 dB and 3° at 4 GHz. the advantage of the dual-gate configuration is that the input impedance conditions are more constant than for the single-gate configuration.