RF and microwave phase shifter using complementary bias techniques

A novel method for the design of an RF phase shifter using a standard foundry process is described. This phase shift achieves very low and near-constant insertion loss. The proposed method uses `complementary' control techniques to keep variable parasitic resistance in a standard transistor to a minimum. Using an only single stage reflection configuration which employs N varactor diodes as a reflection terminator and M varactor diodes, a minimum insertion loss variation can be obtained. The technique is verified by measurement when N=M=1     

Voltage-controlled optical/RF phase shifter

A new fiber-optic device designed to steer the radiation beam of a phased-array antenna has been demonstrated. A radiofrequency (RF) signal at 125 MHz is generated via photomixing at the output of a single-mode fiber-optic interferometer. The phase of the electrical signal is shifted over several cycles in direct proportion to a voltage applied to an optical controller. The controller consists of a Pockels-type optical phase modulator located in one arm of the heterodyne interferometer. Rapid changes in RF phase are feasible. A miniature low-voltage version of the device, based upon integrated optics, is proposed.     

Photonic RF phase shifter and tunable photonic RF notch filter

A new photonic RF phase shifter structure for phased array antennas is presented. It is based on a single dual-output modulator and two optical switches and optical attenuators. This can realize continuous phase shifting of 0/spl deg/-360/spl deg/ without altering the signal amplitude. It has the advantages of wide bandwidth, fast response time, and fine tuning resolution. Experimental results demonstrate phase shifts over a 360/spl deg/ phase range, with RF signal power changes of less than 0.2 dB, which is in close agreement with predictions. A tunable photonic RF notch filter, which is based on the new phase shifter, is also presented. Experimental results demonstrate continuous tuning of the photonic notch filter over a wide tuning range, which covers the full free spectral range, which is in good agreement with predictions.     

A novel wide-band tunable RF phase shifter using a variable opticaldirectional coupler

We present a novel RF phase-shifter design with a usable bandwidth of 80:1. The design is verified through demonstration of a proof of concept device, consisting of a readily available voltage variable optical coupler fabricated from LiNbO₃, combined with an fiber-optic delay line. The design is analyzed theoretically and measurement of the device confirms the predicted range of operation. Methods of extension of this range of operation are discussed     

Low power digital TTL command for 1 bit 60 GHz RF MEMS phase shifter

This paper presents a circuit used to actuate Radio Frequency MicroElectroMechanical Systems (RF MEMS) based phase shifters for 60 GHz beam forming. Wireless transmission in the 60 GHz band show a dramatic free space loss, thus making it mandatory to use antennas with high gain in a desired direction. Beam forming is then necessary to optimize the link budget between communicating nodes. Antenna arrays can be used for beam forming. The work done at LAAS was aiming to provide RF MEMS based phase shifters working with a standard digital command. RF MEMS commonly have high actuation voltages usually obtained with charge pumps. This paper presents a full 1 bit phase shifter with a digital translation part, an analog DC–DC converter, and an RF MEMS based loaded line phase shifter for 60 GHz signals. This converter is built using boost converters as an alternative to the use of charge pumps for driving RF MEMS in the field of wireless communications. Boost converters, despite relatively high current peaks, allow shorter settling times compared to charge pumps.     

Fundamental limitations in RF switching and phase shifting using semiconductor diodes

When semiconductor diodes are used as variable impedance switching elements in RF transmission networks, the maximum power and minimum attenuation depend upon the characteristics of the diodes and the function being performed. Equations and theorems are derived which define these limits for quantized RF control networks used in on-off switches, selection switches, and phase-shift devices. The relationships are quite general and the limits are shown to apply to a wide variety of network configurations. It is shown that the maximum power of a switch is proportional to the maximum RF current of the forward-biased diode and also to the maximum RF voltage when reverse-biased. The maximum power in phase shifters is a sinusoidal function of the phase change required. Minimum attenuation depends upon the switching function performed, the frequency of operation, and a newly defined cutoff frequency which includes diode resistance in both forward-bias and reverse-bias states.     

Surface-acoustic-wave phase shifter using electrical depolarisation

An electrically variable phase shifter employing surface acoustic waves is described that uses electrical depolarisation of a poled PZT ceramic. Phase shifting occurs in a depoling region in which an electric field of variable strength opposes the remanent ferroelectric moment, causing a change in the piezoelectric coupling and surface-wave velocity.     

Microwave phase shifter using optical waveguide structure

A microwave phase shifter with an integrated optics structure with high efficiency is discussed. The structure and the performance of the device are discussed. Microwave phase shifting was carried out using the fabricated phase shifter of titanium diffused LiNbO₃ optical waveguides. The measured voltage to obtain halfwave phase shift for a 800 MHz microwave signal was 7.0 V. The input microwave power was 21 dBm, and the detected output microwave power was -24 dBm, so the microwave insertion loss was calculated to be approximately -45 dB. The optical insertion loss of the device was -12 dB     

A PWM quadrature-booster phase shifter for AC power transmission

The conventional structures used for phase shifters employ quadrature voltage injection controlled by means of on-load tap changers that require considerable maintenance. Line-commutated thyristor structures have been proposed to replace tap changers, but problems related to filter requirements or the number of switches have limited their utilization. This paper proposes a pulse width modulation (PWM) quadrature-booster phase shifter based on a force-commutated AC controller. It offers features such as fast dynamic response, continuous variation of the phase angle with low harmonic injection, and it requires a simple power structure and can be controlled by adjusting the duty cycle of the switches. The operating principles of the proposed phase shifter are analyzed and their feasibility is demonstrated through digital simulation and experimental implementation     

A novel tunable optoelectronic oscillator based on a photonic RF phase shifter

A novel tunable optoelectronic oscillator （OEO） based on a photonic radio frequency （RF） phase shifter is proposed and analyzed, which consists of a dual-drive Mach-Zehnder modulator （DMZM）, a 90° hybrid coupler and a tunable microwave amplifier （TMA）. This tunable OEO has a simple configuration, and the frequency of the oscillating signal can be tuned by adjusting the amplification factor of the tunable amplifier. The simulation results show that the maxi- mum frequency shift from the center oscillation frequency is 1.48 MHz when the amplification factor of the TMA is set at 10.     

Photonic RF phase shifter for harmonic downconversion in phasedarray antenna beam-forming applications

A photonic integrated-optic RF phase shifter for harmonic downconversion in phased array antenna beam-forming applications is presented. The subsystem consists of two integrated optic Mach-Zehnder interferometers fed with a combined signal from the receiving antenna and the local oscillator. This device achieves both phase shifting and harmonic downconversion of incoming RF signals     

Four-step digital p?i?n diode phase shifter in waveguide at C band using two diodes

The purpose of the work was to design a 2 bit reflection-type phase shifter which could be manufactured by a cheap mass-production technique and which utilised two, rather than the usual three, p?i?n diodes. Since these diodes comprise a relatively large fraction of the total cost of the phase shifter, the saving of one diode allows a useful reduction in cost. The phase shifter, which is in reduced-height waveguide and covers the 5275?5475 MHz band, allows the phase of a signal reflected from it to be changed by 90°, 180° and 270°. The letter describes the design and performance of the phase shifter. The phased-array configuration for which it would be appropriate is a large reflect array with, say, 2000 elements.     

Reflection-type continuously-tunable phase shifter using PZT thin-film capacitors

The design, fabrication and performance of a reflection-type tunable phase shifter based on a lead zirconate titanate (PZT) thin-film process is presented. The phase shifter consists of a coplanar waveguide Lange coupler on high resistivity silicon (HRSi) and two ferroelectric PZT varactors. At 12 GHz, the varactors achieve a capacitance tuning range of 5.5 to 1 along with a phase shift of 86° with bias voltages in the range 0?26 V. Analysis of the losses due to the varactors and the rest of the phase shifter is also presented.     

Improved broadband dumb-bell-shaped phase shifter using multi-section stubs

A broadband dumb-bell-shaped 45deg phase shifter is presented using a new design comprised of open-circuit and short-circuit multi-section stubs. A wideband phase shifter operating over the frequency range 2-6 GHz was designed and fabricated for verification purposes. It was measured to have a bandwidth of about 100% for a maximum phase deviation of plusmn3.2deg, and maximum insertion loss of 2.1 dB.     

A 2-bit RF MEMS phase shifter in a thick-film BGA ceramic package

The development of a thick-film hermetic BGA package for a radio-frequency (RF) microelectromechanical systems (MEMS) 2-bit phase shifter is presented. The measured packaged MEMS phase shifter average in-band insertion loss was 1.14 dB with an average return loss of 15.9 dB. The package transition insertion loss was less than 0.1 dB per transition with excellent agreement between simulated and measured results. It was also demonstrated that the RF MEMS phase shift performance could be improved to obtain a phase error of less than 3.3 degrees. The first reported measurements of the average rise and fall times associated with a MEMS circuit (in this case a 2-bit phase shifter) were 26 and 70 /spl mu/s, respectively. The advent of packaged RF MEMS phase shifters will reduce the cost (both design and building) of future phase arrays.     

高效率E类射频功率放大器

研究了E类RF放大器的电路结构、工作原理、存在问题以及解决的方法--差分和交叉耦合反馈结构,最后给出了E类放大器的实例.由于具有低成本、高集成度、多功用等优点,MOS工艺在射频功率放大方面有很大的发展潜力.在本文中,用0.6 u m CMOS工艺实现了E类放大器的设计.     

Linear tunable phase shifter using a left-handed transmission line

We demonstrate a compact, linear, and low loss variation hybrid phase shifter using a left-handed (LH) transmission line. For frequencies from 4.3 to 5.6 GHz, this phase shifter gives a nearly linear phase variation with voltage, with a maximum deviation of /spl plusmn/7.5/spl deg/. Within this frequency range, the maximum insertion loss is 3.6 dB, and the minimum insertion loss is 1.8 dB over a continuously adjustable phase range of more than 125/spl deg/, while minimum return loss is only 10.2 dB. Furthermore, this phase shifter requires only one control line, and it consumes almost no power.     

A precise digital phase shifter using a phase-locked loop

A phase-locked loop containing a voltage-controlled oscillator (v.c.o.) synchronised to a harmonic of its fundamental output frequency may be used to form an attractive digital phase shifter providing low phase error with relatively simple circuitry and control requirements. Phase increments of 2?/n radians are obtained, where n is the order of harmonic used.     

Design,fabrication and characterization of miniature RF MEMS switched capacitor based phase shifter

This paper aims to present in detail the design, fabrication and the various characterization techniques adopted in realizing a novel miniature-size switched capacitor based phase shifter. The work strives to provide an all-round development of a DMTL (Distributed MEMS Transmission Line) based phase shifting unit yielding an overall phase shift of 15° at a frequency of 15 GHz. The RF MEMS (Radio Frequency Micro Electro Mechanical Systems) Switched Capacitor based phase shifter has highly miniaturized dimensions, and is capable of solving many limitations to which the conventional Switched Capacitors are mostly susceptible. This miniature RF MEMS switched capacitor actuates at a low actuation voltage of 12 V, exhibits a fundamental frequency of vibration as high as 1.468 MHz and a switching time of 1.4 µs which is an improvement over the other reported designs. Various characterization results seem to validate the simulations.