Phase Tuning Range Research Articles

Broadband and wide range tunable phase shifter based on composite right/left handed transmission line

In this paper, an improved tunable phase shifter with broadband and wide range of the phase shift is proposed. The structure consists of two improved tunable composite right/left handed (CRLH) transmission line (TL) unit cells. A π-shape circuit model is adopted for each unit cell, and its phase characteristic is discussed in detail, based on which a varactor diode parallel to a lumped capacitor in series circuit and two varactor diodes series with other lumped capacitors in shunt circuits are carefully designed to tune the shifted phase as well as the nonignorable lumped inductors. After that, the phase shifter is finally fabricated using two tunable CRLH-TL unit cells. All of the varactor diodes are controlled by only one bias voltage which also leads to a compact size. The simulated and measured results agree well with a continuously tunable phase range more than 170°. The relative bandwidth is 40%, while the input return loss is not large than 10 dB.

All-optical microwave bandpass filter and phase shifter using a broadband optical source and an optical phase modulator

We propose a system that can perform microwave bandpass filtering and phase shifting simultaneously without redundant optical-electrical and electrical-optical conversions. The principle is based on polarization-dependant phase modulation of a broadband optical source and the variable optical carrier time shift method. A single-bandpass microwave photonic filter with a central frequency of 10.8 GHz, a 3-dB bandwidth of 670 MHz, and a 360° phase tuning range is experimentally demonstrated. The capability of our configuration to implement wideband phase shifters is also verified.

Tunable phase shifter employing variable odd-mode impedance of short-section parallel-coupled microstrip lines

A complete design method for a tunable phase shifter that employs a short section of parallel-coupled microstrip lines is presented. In the proposed method, the variation in the phase is achieved by changing the odd-mode impedance of parallel-coupled microstrip lines using a varactor diode that is connected between them. A derived theoretical model shows that a unit-cell phase shifter of around one-tenth of the guided wavelength can be utilised to achieve a continuously tunable phase range in excess of 90° depending on the required bandwidth and acceptable insertion loss. The proposed method shows that in order to achieve the required tunable phase range across a wideband, high even-mode impedance is needed. A slotted ground structure is utilised underneath the coupled structure to realise that target. The proposed method is validated by building a phase shifter that has a very small length of around one-twentieth of the guided wavelength with 45° tunable phase range and about 1 dB insertion loss across the band from 2 to 2.5 GHz.

High-Q metamaterial interdigital transmission line based on complementary spiral resonators for low phase noise voltage-controlled oscillator

In this study, the high-quality factor ( Q ) metamaterial interdigital transmission line (TL) based on the complementary spiral resonators (CSRs) is presented for reducing the phase noise of the voltage-controlled oscillator (VCO). The high- Q metamaterial TL is realised by adopting the array of the CSRs etched on the ground plane and the interdigital centre line on the signal plane. The interdigital centre line on the signal plane has been used to obtain higher Q value than that of the conventional implementation. The resonance properties and inherent Q value saturation of the proposed high- Q metamaterial interdigital TL have been analysed as follows: width of the centre line on the signal plane, dimensions of the CSRs, current directions between the CSRs, number of the unit cell-pair of the CSRs and whether or not there is the interdigital structure. The phase noise and tuning range of the proposed VCO are -127.50 to -124.87-dBc/Hz at 100-kHz and 5.744-5.86-GHz.

Thermal reliability of VCO using InGaP/GaAs HBTs

Degradations of InGaP/GaAs heterojunction bipolar transistor (HBT) collector current and base current subjected to cumulative long-term junction temperature stress are examined experimentally. The aged SPICE model parameters as a function of stress time are extracted from the measurement data. The VCO phase noise, tuning range, and output amplitude are studied in circuit simulation. The phase noise increases, tuning range and output amplitude decrease with increasing junction temperature.

A K-Band CMOS Phase Shifter MMIC Based on a Tunable Composite Metamaterial

This letter presents a K-band phase shifter monolithic microwave integrated circuit (MMIC) which is based on electrically tunable composite left- and right-handed metamaterials. This structure utilizes both positive and negative phase shifting metamaterial characteristics to allow for a wide tuning range. This is achieved by varying both the capacitance and inductance of the metamaterial structure. The inductance tuning is realized by an improved active inductor with a self-resonant frequency greater than 20 GHz. The phase shifter is divided into four sections of unit cell metamaterial and is implemented in 0.13 μm radio frequency complementary metal-oxide-semiconductor (RFCMOS) technology. The phase shifter exhibits a continuous phase tuning range of 121° (from -80° to +41°) and 136° (from -120° to + 16°) at 21.5 and 22.5 GHz, respectively. The minimum insertion loss is -10.1 and -10.5 dB at 21.5 and 22.5 GHz, respectively. At 26 GHz, a wide phase shift of greater than 300° is achieved in a compact chip area of 0.28 mm2.

Design of a Beam Switching/Steering Butler Matrix for Phased Array System

A compact broadband 8-way Butler matrix integrated with tunable phase shifters is proposed to provide full beam switching/steering capability. The newly designed multilayer stripline Butler matrix exhibits an average insertion loss of 1.1 dB with amplitude variation less than ±2.2 dB and an average phase imbalance of less than 20.7° from 1.6 GHz to 2.8 GHz. The circuit size is only 160 × 100 mm2, which corresponds to an 85% size reduction compared with a comparable conventional microstrip 8-way Butler matrix. The stripline tunable phase shifter is designed based on the asymmetric reflection-type configuration, where a Chebyshev matching network is utilized to convert the port impedance from 50 ? to 25 ? so that a phase tuning range in excess of 120° can be obtained from 1.6 GHz to 2.8 GHz. To demonstrate the beam switching/steering functionality, the proposed tunable Butler matrix is applied to a 1 × 8 antenna array system. The measured radiation patterns show that the beam can be fully steered within a spatial range of 108°.

Design of SIPC‐based complementary LC‐QVCO in 0.18‐μm CMOS technology for WiMAX application

PurposeThe purpose of this paper is to design and realize a low‐phase noise, high‐output power, and high‐tuning range, fully integrated source injection parallel coupled (SIPC)‐based inductor‐capacitor (LC)‐quadrature voltage controlled oscillator (QVCO) covering WiMAX frequency range in 0.18‐μm deep submicron CMOS technology.Design/methodology/approachA pMOS based‐SIPC LC‐QVCO topology is realized with the center frequency of 2.58 GHz. On chip spiral inductor is integrated with substantial quality factor, Q coupled with underlying pattern ground shield (PGS) shielding. An enhanced tuning range is achieved by integrating the diode connected MOS‐based varactors. The CMOS‐based autonomous SIPC LC‐QVCO circuit was characterized for its output phase noise, tuning range and power spectrum response via wafer probing, utilizing a signal source analyzer (Agilent E5052 A).FindingsA quadrature oscillator catering to the needs of local oscillator (LO) generation covering the frequency range of WiMAX is realized. The parallel coupled architecture adapts direct source coupling, bypassing the LC resonator tank and relaxes the close in phase noise up‐conversion. The design consumes 2.19 mm2 of active chip area and measures a phase noise of −114.34 dBc/Hz at 1 MHz of offset frequency with 2.67 GHz of output frequency at 0.9 V of input tuning voltage. The corresponding output power measures to be −10.1 dBm, well suited for mixer hard switching. The design is realized in one poly, six metal 0.18‐μm standard CMOS technology.Research limitations/implicationsOwing to convergence discrepancy in the analysis, a diode‐connected MOS varactor is adapted in contrary to the accumulation mode MOS varactors with superior tuning range.Practical implicationsThe designed SIPC LC‐QVCO is of need in the generation of low‐phase noise, highly matched quadrature LO generation covering the WiMAX frequency range. The adapted parallel coupling also relaxes the voltage headroom limitation.Originality/valueThis paper shows how a fully integrated CMOS‐based SIPC LC‐QVCO architecture is adapted with low‐output phase noise and low voltage headroom consumption covering the WiMAX frequency range.

A Planar Electronically Steerable Patch Array Using Tunable PRI/NRI Phase Shifters

This paper presents a planar electronically steerable series-fed patch array for 2.4-GHz industrial, scientific, and medical band applications. The proposed steerable array uses 0deg tunable positive/negative-refractive-index (PRI/NRI) phase shifters to center its radiation about the broadside direction and allow scanning in both directions off the broadside. Using the PRI/NRI phase shifters also minimizes the squinting of the main beam across the operating bandwidth. The tunable PRI/NRI phase shifters employ 0.13-mum CMOS tunable active inductors, as well as varactors in order to extend their phase tuning range and maintain a low return loss across the entire phase tuning range. The feed network of the proposed array uses lambda/4 impedance transformers. This allows using identical interstage phase shifters, which share the same control voltages to tune all stages. Furthermore, using the impedance transformers in combination with the CMOS-based constant-impedance PRI/NRI phase shifters guarantees a low return loss for the antenna array across its entire scan angle range. The antenna array was fabricated, and is capable of continuously steering its main beam from -27deg to +22deg off the broadside direction with a gain of 8.4 dBi at 2.4 GHz. This is achieved by changing the varactors' control voltage from 3.5 to 15 V. Across the entire scan angle range, the array return loss is less than -10 dB across a bandwidth of 70 MHz, and the relative sidelobe level is always less than -10 dB. Furthermore, the proposed design achieves very low beam squinting of 1.3deg/100 MHz at broadside and a 1-dB compression point of 4.5 dBm.

A Millimeter-Wave CMOS LC-Tank VCO With an Admittance-Transforming Technique

A novel circuit topology suitable for millimeter-wave voltage-controlled oscillators (VCOs) is presented. With the admittance-transforming technique, the proposed VCO can operate at a frequency close to the fmax of the transistors while maintaining remarkable circuit performance in terms of phase noise, tuning range, and output power. Using a standard micrometer CMOS process, a U-band VCO is implemented for demonstration. The fabricated circuit exhibits a frequency tuning range of 1.1 GHz in the vicinity of 50 GHz. The measured output power and phase noise at 1-MHz offset are -11 dBm and -101 dBc/Hz, respectively. Operated at a supply voltage of 1.8 V, the VCO core consumes a DC power of 45 mW.

Electrically Steerable Single-Layer Microstrip Traveling Wave Antenna With Varactor Diode Based Phase Shifters

The design of electrically steerable traveling wave microstrip antenna arrays is presented. Varactor diode based phase shifters implemented on the same metallic layer as the patch elements are used to provide a variable progressive phase shift in the array. Two antennas for the 5.8 GHz ISM band, manufactured as single layer printed designs on a standard PTFE soft substrate, are demonstrated. A ten-element beam-tilting vertical array using transmission type phase shifters is realized, yielding between 11.8 to 13.9 dBi gain for the 0deg to 11deg beam tilt tuning range. Using wide phase tuning range reflection type phase shifters a five-element horizontally scanning array with -32deg to 32deg steering range and 10.9-11.3 dBi gain has been realized.

Printed and Integrated CMOS Positive/Negative Refractive-Index Phase Shifters Using Tunable Active Inductors

This paper presents a printed and an integrated bi-directional tunable positive/negative refractive-index phase shifter utilizing CMOS tunable active inductors (TAIs). The printed phase shifter is comprised of a microstrip transmission line (TL), loaded with series varactors and a shunt monolithic microwave integrated circuit (MMIC) synthesizing the TAI. Using the TAI extends the phase tuning range and results in a low return loss across the entire tuning range. The integrated circuit (IC) phase shifter replaces the TLs with suitable lumped L-C sections. This enables integrating the entire phase shifter on a single MMIC, resulting in a compact implementation. The TAI used for both phase shifters is based on a modified gyrator-C architecture, employing a variable resistance to independently control the inductance and quality factor. The TAI is fabricated in the 0.13-mum CMOS process and operates from a 1.5-V supply. The TAI chip is used to implement the TL phase shifter, which achieves a phase of -40deg to +34deg at 2.5 GHz with less than -19-dB return loss from a single stage occupying 10.8 mm times 10.4 mm. The IC phase shifter is fabricated in the same process and achieves a phase from -35deg to +59deg at 2.6 GHz with less than -19-dB return loss from a single stage occupying 550 mum times 1300 mum.

A High-Performance CMOS Voltage-Controlled Oscillator for Ultra-Low-Voltage Operations

In this paper, a novel circuit topology of voltage-controlled oscillators (VCOs) suitable for ultra-low-voltage operations is presented. By utilizing the capacitive feedback and the forward-body-bias (FBB) technique, the proposed VCO can operate at reduced supply voltage and power consumption while maintaining remarkable circuit performance in terms of phase noise, tuning range, and output swing. Using a standard 0.18-mum CMOS process, a 5.6-GHz VCO is designed and fabricated for demonstration. Consuming a dc power of 3 mW from a 0.6-V supply voltage, the VCO exhibits a frequency tuning range of 8.1% and a phase noise of -118 dBc/Hz at 1-MHz offset frequency. With an FBB for the cross-coupled transistors, the fabricated circuit can operate at a supply voltage as low as 0.4 V. The measured tuning range and phase noise are 6.4% and -114 dBc/Hz, respectively

A 0.13-$\mu$m CMOS Phase Shifter Using Tunable Positive/Negative Refractive Index Transmission Lines

This letter presents a tunable positive/negative refractive index transmission line (TL) phase shifter utilizing active circuits. It comprises a microstrip TL loaded with series varactors and a shunt monolithic microwave integrated circuit (MMIC) to synthesize a tunable inductor. This implementation increases the phase tuning range and maintains the input and output matching of the phase shifter across the entire phase tuning range, while eliminating the need for bulky passive inductors. The phase shifter is capable of providing both positive and negative phase shifts. The MMIC tunable inductors are fabricated in a 0.13-mum CMOS process and operate from a 1.5-V supply. The phase shifter achieves a phase of -40deg to +34deg at 2.5GHz from a single stage with less than -19dB return loss, and better than 1.1-dB insertion loss at 2.5 GHz. The phase shifter has a 1-GHz bandwidth over which the return loss remains better than 12.1dB

On the feasibility of CMOS multiband phase shifters for multiple-antenna transmitters

We present the design of an integrated multiband phase shifter in RF CMOS technology for phased array transmitters. The phase shifter has an embedded classical distributed amplifier for loss compensation. The phase shifter achieves a more than 180/spl deg/ phase tuning range in a 2.4-GHz band and a measured more than 360/spl deg/ phase tuning range in both 3.5-GHz and 5.8-GHz bands. The return loss is less than -10dB at all conditions. The feasibility for transmitter applications is verified through measurements. The output power at a 1-dB compression point (P/sub 1 dB/) is as high as 0.4dBmat 2.4GHz. The relative phase deviation around P/sub 1 dB/ is less than 3/spl deg/. The design is implemented in 0.18-μmRF CMOS technology, and the chip size is 1200μm × 2300 μm including pads.

Development of multiband phase shifters in 180-nm RF CMOS technology with active loss compensation

We present the design and development of a novel integrated multiband phase shifter that has an embedded distributed amplifier for loss compensation in 0.18-/spl mu/m RF CMOS technology. The phase shifter achieves a measured 180/spl deg/ phase tuning range in a 2.4-GHz band and a measured 360/spl deg/ phase tuning range in both 3.5- and 5.8-GHz bands. The gain in the 2.4-GHz band varies from 0.14 to 6.6 dB during phase tuning. The insertion loss varies from -3.7 dB to 5.4-dB gain and -4.5 dB to 2.1-dB gain in the 3.5- and 5.8-GHz bands, respectively. The gain variation can be calibrated by adaptively tuning the bias condition of the embedded amplifier to yield a flat gain during phase tuning. The return loss is less than -10 dB at all conditions. The chip size is 1200 /spl mu/m/spl times/2300 /spl mu/m including pads.

Coarse–fine, wideband distributed voltage controlled oscillator for wireless applications

A new distributed voltage controlled oscillator (DVCO) is presented. The proposed topology allows a very wide tuning range VCO and fine-coarse tuning. The design of a prototype DVCO is discussed and measurements are reported showing improved performance in terms of phase noise, tuning range and power consumption.

A 17-GHz 130-nm CMOS VCO subsystem module in LTCC-based technology for WLAN applications

This article presents a 17-GHz band VCO for system-in-a-package (SiP) solutions. A workflow for a chip-package codesign, which includes the design of LTCC-inductors, is presented. The VCO shows a phase noise of −110 dBc/Hz at 1-MHz offset and a figure of merit (FOM) of −190.4 dBc/Hz. Design trade-offs are given concerning phase noise, tuning range, and power consumption. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.

Dual-band ultra-wide tuning range CMOS voltage-controlled oscillator

A dual-band wide-tuning range LC CMOS voltage controlled oscillator (VCO) topology is proposed. Dual-band operation is realised by employing a double-tuned double-driven transformer as a resonator. The proposed approach eliminates MOS switches, which are typically used in multi-standard oscillators, and thus improves phase noise and tuning range characteristics. The concept is demonstrated through the design of an LC VCO in a standard 0.18 µm CMOS process. Two frequency bands are realised (2.4 and 6 GHz) with 740 MHz tuning range in the first band and 1.56 GHz tuning range in the second band. Operating from a 1.8 V supply, the VCO has a simulated phase noise of −119 dBc/Hz in the 2.4 GHz band and −110 dBc/Hz in the 6 GHz band at 600 KHz offset from the carrier.

Compact reflective microstrip phase shifter for traveling wave antenna applications

A varactor diode based microstrip phase shifter for 5.8GHz is presented. It is designed for use in microstrip traveling wave antennas where there is a strict limitation on the available space for the phase shifters. To meet all requirements, a reflective type phase shifter is chosen. Such a phase shifter includes a hybrid coupler. A compact branch line coupler is designed to make the phase shifter fit between the radiating elements in the antenna, while maintaining sufficient electrical performance. Phase shifters are designed with different types of stubs connecting the diodes to ground. A phase tuning range of 62deg is measured for a phase shifter with parallel open stubs, and 92deg with shorted stubs. Insertion loss is in both cases less than 0.6dB. A complete five-element array antenna is built and characterized. Measurements show beam scanning angles within plusmn32deg from broadside