Design considerations for integrated CMOS reflective-type phase shifters

An analysis of reflective-type phase shifters with transformed single-resonant loads for integrated CMOS phased-array implementations is presented. Several components of the standard lumped-element coupler can be eliminated without significant performance degradation, to allow more compact implementations. It is found that the varactor should be chosen as small as feasible to minimize sensitivity to parasitic resistance. Larger varactors reduce sensitivity to parasitic capacitance, but this can be compensated for in the phase shifter design. A general design procedure for reflective-type phase shifters is given. A phase shifter operating at 2.0 GHz has been designed and implemented in a 0.18 μm CMOS process using the design procedures outlined, and it occupies an area of 0.75 mm² and consumes 6.8 mW of power. The measured phase shift range is 308° for a control voltage varying from 0–1.8 V, which to our knowledge is the largest phase shift range of any CMOS reflective-type phase shifter reported to date.     

Design and performance of a Ka-band monolithic phase shifterutilizing nonresonant FET switches

This paper describes design consideration and performance of a Ka-band monolithic phase shifter utilizing nonresonant FET switches. The switches show broad-band on/off characteristics up to 60 GHz without using inductors; thus, robust circuit design is possible for a switched-line phase shifter. To determine circuit topology, we introduce a schematic design approach. As a result, desired phase shift as well as good matching characteristics can be realized. The developed 4-bit monolithic phase shifter demonstrates an overall phase deviation less than 5° rms and an insertion loss variation less than 0.65 dB rms from 33 to 35 GHz. For all 16 states, the insertion loss is measured to be 13.1±1.1 dB and the VSWR is less than 1.6. The chip size of the monolithic phase shifter is 2.5 mm×2.2 mm     

2.4 GHz continuously variable ferroelectric phase shifters using all-pass networks

Continuously variable ferroelectric (BST on sapphire) phase shifters based on all-pass networks are presented. An all-pass network phase shifter consists of only lumped LC elements, and thus the total size of the phase shifter is kept to less than 2.2 mm /spl times/ 2.6 mm at 2.4 GHz. The tunability (C/sub max//C/sub min/) of a BST interdigital capacitor is over 2.9 with a bias voltage of 140 V. The phase shifter provides more than 121/spl deg/ phase shift with the maximum insertion loss of 1.8 dB and the worst case return loss of 12.5 dB from 2.4 GHz to 2.5 GHz. By cascading two identical phase shifters, more than 255/spl deg/ phase shift is obtained with the maximum insertion loss of 3.75 dB. The loss figure-of-merit of both the single- and double-section phase shifters is over 65/spl deg//dB from 2.4 GHz to 2.5 GHz.     

Electrically Tunable Reflective Terahertz Phase Shifter Based on Liquid Crystal

We present a reflective spatial phase shifter which operates at terahertz regime above 325 GHz. The controllable permittivity of the nematic liquid crystals was utilized to realize a tunable terahertz (THz) reflective phase shifter. The reflective characteristics of the terahertz electromagnetic waves and the liquid crystal parameters were calculated and analyzed. We provide the simulation results for the effect of the incident angle of the plane wave on the reflection. The experiment was carried out considering an array consisting of 30?×?30 patch elements, printed on a 20?×?20 mm quartz substrate with 1-mm thickness. The phase shifter provides a tunable phase range of 300° over the frequency range of 325 to 337.6 GHz. The maximum phase shift of 331° is achieved at 330 GHz. The proposed phase shifter is a potential candidate for THz applications, particularly for reconfigurable reflectarrays.     

Phase Shifter for a 915 MHz Phased Array Hyperthermia System

This paper describes a design for an analog phase shifter operating at 915 MHz and suitable for use in a phased array microwave hyperthermia system. Here, the major operating constraint was minimization of amplitude variation over a 1800 phase shift, whereas previous phase shifters were designed to obtain a linear relationship between phase and control voltage. The result is a simple, inexpensive hybrid coupler phase shifter that operates over a narrow bandwidth and provides 180°of continuous phase shift with input powers up to 1 W.     

Design and performance of a new digital phase shifter at X-band

A new digital phase shifter design at X-band is presented. The phase shifter operates based on converting a microstrip line to a rectangular waveguide and thus achieving the phase shift by changing the wave propagation constant through the medium. As a proof of principle, a 3-b phase shifter has been designed and constructed using PIN diode switches. An average insertion loss of 1.95 dB and phase shift error of less than 4/spl deg/ at 10.6 GHz are achieved.     

A 500 kW X-Band Air-Cooled Ferrite Latching Switch

The design of a high-power air-cooled microwave SPDT switch which is capable of operation at peak and average power levels of 500 kW and 666 watts, respectively, is described. The unit is of a differential phase shift circulator design employing 90/spl deg/ nonreciprocal phase shift elements which are forced air cooled. The phase shifter design employs dual ferrite toroids, "floating" in reduced height RG-51 waveguide. Two approaches are compared for heat sinking the phase shifter; namely the "H-beam" and the "I-beam" configurations. The results obtained indicate that the I-beam configuration is superior to the "H-beam" configuration. The switch exhibits an insertion loss of 0.6 dB maximum and isolation greater than 20 dB over a 100 MHz bandwidth centered at 9.375 GHz. The input VSWR of the switch over the frequency band is less than 1.28:1.     

A K-Band Low-Power Phase Shifter Based on Injection Locked Oscillator in 0.13 μm CMOS Technology

In this paper, the design challenges of the injection-locked oscillator (ILO)-based phase shifter are reviewed and analyzed. The key design considerations such as the operating frequency, locking range, and linearity of the phase shifters are analysed in detail. It is possible to optimize the phase shifter in certain parameters such as ultra-low power while meeting the requirements of a certain system. As a design example, a K-band phase shifter is implemented using a commercial 0.13 μm CMOS technology, where a conventional LC tank based topology is implemented but optimised with a good balance among power consumption, working range, sensitivity, and silicon area, etc. Measurement results show that the proposed phase shift is able to work at 22–23.4 GHz with a range of 180^° while consuming 3.14 mW from a 1.2 V supply voltage.     

A hybrid phase shifter circuit based on TlCaBaCuO superconductingthin films

A superconductor-semiconductor hybrid reflection-type phase shifter circuit has been designed, fabricated, and characterized for 180° phase bit with center frequency of 4 GHz and bandwidth of 0.5 GHz for operation at 77 K. All of the passive components of the phase shifter circuit such as input/output feed lines, 3 dB Lange coupler, impedance matching networks, and transmission lines consisted of thallium based superconducting TlCaBaCuO thin films of 4000 Å thickness on lanthanum aluminate substrate. Metal-Schottky field-effect-transistors (MESFET's) on GaAs semiconductor were used as active devices for switching action (on-state and off-state) in the phase shifter circuit. The phase shift and insertion losses were investigated as a function of frequency from 3.6 to 4.6 GHz at 77 K. The circuit exhibited a fairly flat response of 180° phase shift with a maximum deviation of less than 2° and a maximum insertion loss of 2 dB for on-state and 2.2 dB for off-state conditions over 0.5 GHz bandwidth at 4 GHz. The insertion losses were also fairly flat within the bandwidth. The insertion losses were constant between 50 and 80 K, giving the circuit a large range of operation at or below 77 K. The performance of this circuit as compared to a gold microstrip-semiconductor circuit designed identically was superior by a factor of 1.5, and may be due to lower conductor losses and lower surface resistance in the superconducting microstrips     

Continuous Varactor-Diode Phase Shifter with Optimized Frequency Response

A method is introduced for designing continuous varactor-diode phase shifters with optimum frequency response. The circuit used gives very small frequency variations of the phase shift if the maximum phase shift of the device is less than about 200/spl deg/. Measurement results on a 180/spl deg/ L-band phase shifter are presented. This unit gives less than 5/spl deg/ variation of any given phase shift less than 180/spl deg/, when the frequency is changed from 1.5 to 1.7 GHz.     

Low loss 360° Ku band electronically reconfigurable phase shifter

The aim of the paper below is to present the design approach, manufacture process and measurement results of a complete 360^°${360}^{°}$ phase shifter for Ku band controlled electronically. The phase shifter is based on microstrip technology and tunable reflective lines with varactor technology. This device allows to establish more than 360° phase variation with low insertion losses (2 dB in average), compared with devices found in literature. In this paper, a 12 GHz tunable phase shifter is analyzed, designed, simulated and prototyped. Eventually, prototype measurements are shown.     

0.13-μm CMOS Phase Shifters for X-, Ku-, and K-Band Phased Arrays

Two 4-bit active phase shifters integrated with all digital control circuitry in 0.13-mum RF CMOS technology are developed for X- and Ku-band (8-18 GHz) and K-band (18-26 GHz) phased arrays, respectively. The active digital phase shifters synthesize the required phase using a phase interpolation process by adding quadrature-phased input signals. The designs are based on a resonance-based quadrature all-pass filter for quadrature signaling with minimum loss and wide operation bandwidth. Both phase shifters can change phases with less than about 2 dB of RMS amplitude imbalance for all phase states through an associated DAC control. For the X- and Ku-band phase shifter, the RMS phase error is less than 10^o over the entire 5-18 GHz range. The average insertion loss ranges from to at 5-20 GHz. The input for all 4-bit phase states is typically at -5.4 plusmn1.3 GHz in the X- and Ku-band phase shifter. The K-band phase shifter exhibits 6.5-13 of RMS phase error at 15-26 GHz. The average insertion loss is from 4.6 to at 15-26 GHz. The input of the K-band phase shifter is at 24 GHz. For both phase shifters, the core size excluding all the pads and the output 50 Omega matching circuits, inserted for measurement purpose only, is very small, 0.33times0.43 mm² . The total current consumption is 5.8 mA in the X- and Ku-band phase shifter and 7.8 mA in the K-band phase shifter, from a 1.5 V supply voltage.     

A Dual-Mode Latching Reciprocal Ferrite Phase Shifter

A ferrite phase shifter has been developed to provide latching reciprocal phase shift over a moderate frequency band. The principle of operation is based on the use of dual-mode circularly polarized waves in the active ferrite with nonreciprocal polarizers to select modes that provide reciprocal transmission phase. The physical structure of the phase shifter consists of a metallized assembly of ferrite and ceramic dielectric. A ferrite yoke is fitted over a portion of this assembly to permit latching operation. The completed phase shifter has a very simple geometry that can be produced at low cost and has relatively low insertion loss. The maximum cross-sectional dimensions are small and are consequently compatible with application in two-dimensional electronically scanned arrays. Experimental results are presented for an X-band design having a 10-percent bandwidth centered near 9 GHz.     

Ka波段开关线型MEMS移相器的设计与研究

面向现代通信及相控阵雷达领域的需求,设计了一种移相间隔为22.5°的Ka波段4位开关线型射频MEMS移相器。主要对实现移相功能的四个移相单元进行了设计,采用台阶补偿技术优化移相单元上下通路分工选通,以提供最佳的阻抗匹配;采用直角转角结构,设计了可提高CPW直角性能的延迟线,并对应用该延迟线的4位开关线型移相器进行了总体设计。用HFSS进行建模仿真,结果表明,在0~40 GHz工作频段内,16个状态的插入损耗均小于2.15 dB,回波损耗均大于19.18 dB,驻波比均小于1.25,在40 GHz频点处的相移误差在1.57°以内,整体尺寸为10 mm²。     

A Full-360° Reflection-Type Phase Shifter With Constant Insertion Loss

A new reflection-type phase shifter with a full 360deg relative phase shift range and constant insertion loss is presented. This feature is obtained by incorporating a new cascaded connection of varactors into the impedance-transforming quadrature coupler. The required reactance variation of a varactor can be reduced by controlling the impedance ratio of the quadrature coupler. The implemented phase shifter achieves a measured maximal relative phase shift of 407deg, an averaged insertion loss of 4.4 dB and return losses better than 19 dB at 2 GHz. The insertion-loss variation is within plusmn0.1 and plusmn0.2 dB over the 360deg and 407deg relative phase shift tuning range, respectively.     

An MMIC active phase shifter using a variable resonant circuit [andMESFETs]

This paper describes a monolithic-microwave integrated-circuit (MMIC) active phase shifter using a variable resonant circuit with a large amount of variable phase. We first propose a novel active phase-shifter configuration that uses a variable resonant circuit with second-order all-pass network characteristics. Phase can be changed with a constant amplitude by varying the capacitance or the inductance of the resonant circuit. Next, an experimental MMIC active phase shifter with input active matching is presented. A phase shift of over 100° and an insertion loss of 4±1 dB are obtained from 2.2 to 2.8 GHz. The chip size is less than 1.0 mm². Finally, an experimental 360° MMIC active phase shifter is presented. Over the bandwidth of 40 MHz at 2.44 GHz, the insertion gain is 2.0±0.7 dB and the phase error is within ±4° when measured in 30° steps     

A production ready, 6-18-GHz, 5-b phase shifter with integratedCMOS compatible digital interface circuitry

A producible, high-yield, monolithic 6-18-GHz, 5-b phase shifter with integrated standard CMOS compatible digital interface circuitry has been developed for use over the -55 to +90°C temperature range. Differential phase shift is achieved using high-pass and low-pass filter structures. The integrated digital interface circuitry produces complementary outputs that are used to bias the phase-shifter bits. The integration of the digital interface circuitry, made with microwave FETs, reduced the phase-shifter bit control bias lines by a factor of 2. The phase shifter was fabricated at both Raytheon's and Texas Instruments' GaAs foundries in production quantities using a standard microwave process. Complete on-wafer RF tests were performed to screen the phase-shifter circuits and determine electrical yield. The phase shifter has an r.m.s. phase error <10° from 6.5 to 18 GHz, maximum insertion loss of 14 dB, and an r.m.s. amplitude error <0.8 dB over the 6-18-GHz band     

A 4-bit CMOS Phase Shifter Using Distributed Active Switches

This paper presents a novel 4-bit phase shifter using distributed active switches in 0.18-mum RF CMOS technology. The relative phase shift, which varies from 0deg to 360deg in steps of 22.5deg, is achieved with a 3-bit distributed phase shifter and a 180deg high-pass/low-pass phase shifter. The distributed phase shifter is implemented using distributed active switches that consist of a periodic placement of series inductors and cascode transistors, thereby obtaining linear phase shift versus frequency with a digital control. The design guideline of the distributed phase shifter is presented. The 4-bit phase shifter achieves 3.5 plusmn 0.5 dB of gain, with an rms phase error of 2.6deg at a center frequency of 12.1 GHz. The input and output return losses are less than -15 dB at all conditions. The chip size is 1880 mum times 915 mum including the probing pads.     

Ultra compact, low loss, varactor tuned phase shifter MMIC atC-band

This paper presents a high yield, ultra compact, low loss phase shifter MMIC, realized with a commercial 0.6 μm GaAs MESFET process. Phase shift is enabled by varying the varactor capacitances of the lumped element equivalent of a transmission line. Continuously adjustable phase control over 90° is achieved from 4 GHz up to 6 GHz, with a loss of less than 2.2 dB. At 5.2 GHz, a loss of 1.2 dB and a loss variation of ±0.5 dB is measured. Phase and loss variations for several circuits from different wafers are within ±1° and ±0.1 dB, respectively, indicating low dependences on process variations. The phase shifter requires a circuit size of only 0.2 mm², which to our knowledge is the smallest size for a continuously adjustable passive phase shifter with comparable performance, reported to date     

A Continuously Variable Dielectric Phase Shifter (Correspondence)

A stripline phase shifter is described which yields a linear variable phase shift versus frequency. The phase shift is accomplished by varying the dielectric constant of the medium through which the signal propagates. Characteristic impedance is kept constant at all phase shift settings; hence, in theory, no reflections are produced. Measurements made over the 1 to 2 GHz band show the maximum voltage standing-wave ratio (VSWR) to be 1.15. Measured values of insertion phase shift over the same frequency band show good agreement with theory (maximum difference about 2.5 percent).