Showing papers on "Balun published in 2010"

Balanced metamaterial antenna device

Abstract: This document describes designs and techniques for directly feeding an unbalanced transmission line with a balanced antenna using Composite Right and Left Handed (CRLH) and balun structures.

Narrow gauge high strength choked wet tip microwave ablation antenna

Abstract: An electromagnetic surgical ablation probe having a coaxial feedline and cooling chamber is disclosed. The disclosed probe includes a dipole antenna arrangement having a radiating section, a distal tip coupled to a distal end of the radiating section, and a ring-like balun short, or choke, which may control a radiation pattern of the probe. A conductive tube disposed coaxially around the balun short includes at least one fluid conduit which provides coolant, such as dionized water, to a cooling chamber defined within the probe. A radiofrequency transparent catheter forms an outer surface of the probe and may include a lubricious coating.

Compact Hybrid Resonator With Series and Shunt Resonances Used in Miniaturized Filters and Balun Filters

Abstract: A hybrid resonant circuit is proposed in this paper. The circuit is a combination of a shunt resonant circuit and series resonant circuit. With this combination, lower resonant frequency is achieved as compared to the single shunt and series resonant circuits. As a result, a compact resonator with smaller size can be achieved as compared to the conventional quarter- and half-wave resonators. Besides the size reduction, the proposed resonant circuit is able to introduce a transmission zero to improve the stopband suppression in filter design. Based on this circuit, a very compact interdigital coupled microstrip resonator is proposed in this paper. The resonator achieves a small length of nearly 1/10 guided wavelength (?g), which has a length reduction of 63% as compared to the conventional uniform quarter-wave resonator. By using the proposed resonator, a second-order bandpass filter with a small size of 0.144?g × 0.128?g and a fourth-order bandpass filter with a size of 0.217?g × 0.1?g are built based on the standard filter synthesis methods. Both good performance and miniaturization are achieved for the proposed filters, and the expected transmission zeros are also observed. In addition to the small filters, the proposed resonator is suitable for miniaturized balun bandpass filters. A novel configuration for a balun bandpass filter is proposed based on the aforementioned resonators. A second-order balun bandpass filter with a size of 0.26?g × 0.145?g and afourth-order balun bandpass filter with a size of 0.213?g × 0.203?g are reported in this paper. Both balun filters achieve good filtering performance, as well as excellent amplitude and phase imbalances, which are less than 1 dB and 1° in the passband, respectively.

Wideband and High-Gain Composite Cavity-Backed Crossed Triangular Bowtie Dipoles for Circularly Polarized Radiation

Abstract: A composite cavity-backed antenna excited by crossed triangular bowtie dipoles is proposed and investigated for circular polarization (CP) applications. It is fed by a novel balun, i.e., a transition from a microstrip line to double slot lines, providing symmetrical electric field distributions at the feeding port. Measurements of an optimized antenna prototype show that it can achieve an impedance bandwidth of over 57.6% for SWR ≤ 2, a 3-dB axial-ratio bandwidth of 39%, a broadside gain of 8-10.7 dBi, and symmetrical radiation patterns over the whole operating band. The operating principles of the proposed antenna are analyzed carefully and found quite different from crossed thin-wire dipoles with very weak coupling. Problems in the feeding balun, greatly deteriorating the CP performance at the resonance, are clearly addressed and solved. Detailed parametric studies are given in the final part of this paper.

A CMOS Active Feedback Balun-LNA With High IIP2 for Wideband Digital TV Receivers

Abstract: A wideband active feedback single-to-differential (S-to-D) low-noise amplifier (LNA) for digital TV (DTV) tuners composed of a S-to-D converter, a voltage combiner, and a negative feedback network is proposed to achieve low noise as well as to improve the linearity performances (IIP2 and IIP3) simultaneously. By feeding the single-ended output of the voltage combiner, which is used for combining the differential output of the S-to-D converter, to the input of the LNA through the feedback network, a wideband S-to-D LNA exploiting negative feedback is implemented. The differential mode operation of the voltage combiner reduces the second-order nonlinearity feedback, allowing us to improve both the IIP3 and IIP2 of the LNA at the same time. Two LNA design examples are presented to demonstrate usefulness of the proposed approach. The LNA I, by adopting a common source (CS) amplifier with a common gate, common source (CGCS) balun load as the S-to-D converter, is able to achieve a high gain and a low noise figure (NF) by increasing the loop gain. The LNA II using the differential amplifier with the ac-grounded second input terminal is designed for robust IIP2 to PVT variations.

Linearized Dual-Band Power Amplifiers With Integrated Baluns in 65 nm CMOS for a 2 $\, \times \,$ 2 802.11n MIMO WLAN SoC

Abstract: Fully integrated dual-band power amplifiers with on-chip baluns for 802.11n MIMO WLAN applications are presented. With a 3.3 V supply, the PAs produce a saturated output power of 28.3 dBm and 26.7 dBm with peak drain efficiency of 35.3% and 25.3% for the 2.4 GHz and 5 GHz bands, respectively. By utilizing multiple fully self-contained linearization algorithms, an EVM of -25 dB is achieved at 22.4 dBm for the 2.4 GHz band and 20.5 dBm for the 5 GHz band while transmitting 54 Mbs OFDM. The chip is fabricated in standard 65 nm CMOS and the PAs occupy 0.31 mm2 (2.4 GHz) and 0.27 mm2 (5 GHz) area. To examine the reliability of the PAs, accelerated aging tests are performed for several hundreds parts without a single failure.

Linearized Dual-Band Power Amplifiers With Integrated Baluns in 65 nm CMOS for a 2 × 2 802.11n MIMO WLAN SoC

Abstract: Fully integrated dual-band power amplifiers with on-chip baluns for 802.11n MIMO WLAN applications are presented. With a 3.3 V supply, the PAs produce a saturated output power of 28.3 dBm and 26.7 dBm with peak drain efficiency of 35.3% and 25.3% for the 2.4 GHz and 5 GHz bands, respectively. By utilizing multiple fully self-contained linearization algorithms, an EVM of -25 dB is achieved at 22.4 dBm for the 2.4 GHz band and 20.5 dBm for the 5 GHz band while transmitting 54 Mbs OFDM. The chip is fabricated in standard 65 nm CMOS and the PAs occupy 0.31 mm 2 (2.4 GHz) and 0.27 mm 2 (5 GHz) area. To examine the reliability of the PAs, accelerated aging tests are performed for several hundreds parts without a single failure.

Wideband substrate integrated printed log-periodic dipole array antenna

Abstract: This study presents a novel approach for designing broadband single layer printed log-periodic dipole array (PLPDA) antenna fed by substrate integrated waveguide (SIW). The PLPDA antenna has the merits of wide bandwidth, low profile and light weight, which should be fed by the balanced line. The balanced line, created by the geometric features of the SIW, provides a balun with a considerably wide bandwidth with low profile, broad dominant mode bandwidth, low insertion loss and so on. Prototype of the proposed substrate integrated printed log-periodic dipole array (SIPLPDA) antenna and 1×4 antenna array at Ka band are designed and fabricated; the measured data are in good agreement with the simulated results.

Low noise amplifier with combined input matching, balun, and transmit/receive switch

Abstract: A low noise amplifier (LNA) with combined input matching, balun, and/or transmit/receive (T /K) switch is described. In one exemplary design, an apparatus includes a coupled inductor and an LNA. The coupled inductor receives a single-ended input signal, performs single-ended to differential conversion, and provides a differential input signal. The LNA receives and amplifies the differential input signal and provides a differential output signal. The coupled inductor includes magnetically coupled first and second coils. The first coil provides input impedance matching when the LNA is enabled. A resonator circuit formed with the first coil provides high input impedance when the LNA is disabled. A tuning capacitor coupled to the second coil provides amplitude imbalance tuning for the differential input signal. A transmit switch is coupled between the first coil and a transmitter.

A New Broadband Marchand Balun Using Slot-Coupled Microstrip Lines

Abstract: In this letter, a new broadband Marchand balun is proposed using slot-coupled microstrip lines. The developed balun is connected by two sections of diamond-shape slot-coupled microstrips with short- and open-circuited terminations at specified ports. To achieve the broadband operation, the simple formulas have been derived to convert the conventional rectangular-shape slot-coupled microstrip to the diamond-shape counterpart. The measured results of the developed balun not only agree with the full-wave simulation results very well, but also resemble the calculated results by ideal coupled lines. The new Marchand balun developed in this letter has a 10 dB return loss bandwidth of 90%, while in this frequency range the amplitude imbalance varies from -0.37 dB to 0.32 dB, and the phase difference in the range of -180.4° ~ -181.8°.

Full 360 $^{\circ }$ Vector-Sum Phase-Shifter for Microwave System Applications

Abstract: An innovative vector-sum phase shifter with a full 360° variable phase-shift range is proposed and experimentally demonstrated in this paper. It employs an active balun and a very high-speed CMOS operational transconductance amplifier (OTA) integrator to generate the four quadrature basis vector signals. The fabricated chip operates in the 2-3 GHz, it exhibits an average insertion gain of 1.5 dB at midband, and has an RMS phase error below 5° over the measured frequency span. The chip consumes 24 mW of DC power and is highly compact, measuring only 0.38 mm2 including bonding pads.

Transmit architecture for wireless multi-mode applications

Abstract: In one embodiment, an apparatus includes an upconversion unit configured to upconvert a baseband signal to a radio frequency (RF) signal. A plurality of baluns for a plurality of wireless bands are provided. Multiplexing circuitry is coupled to the plurality of baluns where the upconversion unit is coupled to each balun through the multiplexing circuitry. The multiplexing circuitry is configured to multiplex the radio frequency signal from the upconversion unit to one of the plurality of baluns based on a wireless band being used.

A 65nm CMOS quad-band SAW-less receiver for GSM/GPRS/EDGE

Abstract: A quad-band 2.5G receiver integrates the front-end SAW filters, the LNA matching, as well as the RF baluns, achieving a typical sensitivity of close to −111dBm. Utilizing an arrangement of only four baseband capacitors and MOS switches driven by 4-phase 25% duty-cycle clocks, high-Q BPF's are realized to attenuate the 0dBm out-of-band blocker. The SAW-less receiver draws 55mA from the battery, and measures an out-of-band 1dB-compression of greater than +2dBm.

A differential 4-path highly linear widely tunable on-chip band-pass filter

Abstract: A passive switched capacitor RF band-pass filter with clock controlled center frequency is realized in 65nm CMOS. An off-chip transformer which acts as a balun, improves filter-Q and realizes impedance matching. The differential architecture reduces clock-leakage and suppresses selectivity around even harmonics of the clock. The filter has a constant −3dB bandwidth of 35MHz and can be tuned from 100MHz up to 1GHz. IIP3 is better than 19dBm, P 1dB =2dBm and NF≪5.5dB at P diss =2mW to 16mW.

Dual-Mode Dual-Band Bandpass Filter Using Balun Structure for Single Substrate Configuration

Abstract: A novel dual-mode dual-band bandpass filter (BPF) for a single substrate configuration is proposed that uses a balun structure. The outer and inner loop resonators are simultaneously excited by the microstrip line and slotline balun structure. In spite of the microstrip feed network, the proposed dual-mode BPF can achieve dual-band operation. Two proper degenerate modes in the lower and upper passbands can be generated and controlled by installing an inductive cut and a capacitive patch in the corner of two loops, respectively. This letter deals with the analysis and design of the proposed dual-band BPF as well as the experimental validation of the predicted dual-band performance.

Broadband planar wide-scan array employing tightly coupled elements and integrated balun

Abstract: In this paper we present the design, fabrication and demonstration of an X-band phased array capable of wide-angle scanning. A new non-symmetric element for wideband tightly coupled dipole arrays is integrated with a low-profile microstrip balun printed on the array ground plane. The feed connects to the array aperture with vertical twin-wire transmission lines that concurrently perform impedance matching. The proposed element arms are identical near the center feed portion but dissimilar towards the ends, forming a ball-and-cup. A 64 element array prototype is verified experimentally and compared to numerical simulation. The array aperture is placed λ/7 (at 8 GHz) above a ground plane and shown to maintain a VSWR < 2 from 8–12.5 GHz while scanning up to 75° and 60° in E and H-plane, respectively.

New Designs of Bandpass Diplexer and Switchplexer Based on Parallel-Coupled Bandpass Filters

Abstract: In this paper, new designs of a bandpass diplexer and switchplexer are presented. Based on the proposed design method, they can be implemented by the direct connection of two parallel-coupled bandpass filters. As a result, the circuit size and mismatch losses can be reduced compared with conventional designs. In addition, based on the proposed filter prototypes, multiple functional blocks in the RF front end can be integrated into a single component. As an example, a balun-integrated bandpass switchplexer that effectively integrates all the functional blocks between the antenna and the TX/RX amplifiers in a single-band RF transceiver is demonstrated. In this way, not only can the level of integration of the RF front end be further improved, but the circuit size and power losses can also be reduced.

A CMOS Outphasing Power Amplifier With Integrated Single-Ended

Abstract: This brief proposes an on-chip outphasing power amplifier that uses a single-ended Chireix combiner for a linear amplification with a nonlinear component amplifier. The pro- posed combiner structure consists of a lumped inductor and a lumped capacitor that can achieve the simple single-ended configuration of a Chireix combiner. It is also suitable for on-chip implementation with minimum efficiency deterioration. An inductance-capacitance balun using the lumped model of λ/4 and 3λ/4 transmission lines was effectively merged into a simple Chireix combiner for two outphased input signals. The relation between the output resistance and the outphasing angle of the input signals was derived to determine the maximum efficiency. A voltage-mode class-D power amplifier was used with the combiner to illustrate the combiner's effectiveness. The prototype fabricated in a 0.13-μm complementary metal-oxide-semiconductor process shows a maximum 52% power-added efficiency (continuous wave) and a �47-dBc adjacent channel power ratio performance at a 10-MHz offset with a 1.92-GHz wideband code-division multiple- access signal.

Wideband balun having a single primary and multiple secondaries

Abstract: An RF transmitter capable of transmitting over a wide range of frequencies includes a mixer, a wideband high-Q balun, a first driver amplifier and a second driver amplifier. The balun has a single primary winding and two secondary windings. A differential output of the mixer is coupled to the primary winding. A first of the two secondary windings is coupled to drive the first driver amplifier. A second of the two secondary windings is coupled to drive the second driver amplifier. One driver amplifier is used when transmitting at lower frequencies whereas the other driver amplifier is used when transmitting at higher frequencies. By appropriate sizing of the inductances of the secondary windings and by switching out one of the secondary windings at certain times, the balun is tunable to operate over the wide frequency range while having a high quality factor Q, thereby facilitating reduced power consumption while simultaneously meeting performance requirements.

A CMOS Outphasing Power Amplifier With Integrated Single-Ended Chireix Combiner

Abstract: This brief proposes an on-chip outphasing power amplifier that uses a single-ended Chireix combiner for a linear amplification with a nonlinear component amplifier. The proposed combiner structure consists of a lumped inductor and a lumped capacitor that can achieve the simple single-ended configuration of a Chireix combiner. It is also suitable for on-chip implementation with minimum efficiency deterioration. An inductance-capacitance balun using the lumped model of λ/4 and 3λ/4 transmission lines was effectively merged into a simple Chireix combiner for two outphased input signals. The relation between the output resistance and the outphasing angle of the input signals was derived to determine the maximum efficiency. A voltage-mode class-D power amplifier was used with the combiner to illustrate the combiner's effectiveness. The prototype fabricated in a 0.13-μm complementary metal-oxide-semiconductor process shows a maximum 52% power-added efficiency (continuous wave) and a -47-dBc adjacent channel power ratio performance at a 10-MHz offset with a 1.92-GHz wideband code-division multiple-access signal.

Circular array of wideband 3D Vivaldi antennas

Abstract: This communication presents a novel 3D Vivaldi antenna array with 4∶1 bandwidth without the need for balun feeding. A circular array of 8 elements of this 3D Vivaldi antenna is simulated using the Array Scanning Method applied to Method of Moments. It is found that connecting the antennas provides a smoother frequency response. The array is well suited for wideband direction finding with good polarimetric sensitivity. Its calibration made easy by the circular symmetry of the structure.

100 W GaN HEMT power amplifier module with > 60% efficiency over 100–1000 MHz bandwidth

Abstract: We have demonstrated a decade bandwidth 100 W GaN HEMT power amplifier module with 15.5–18.6 dB gain, 104–121 W CW output power and 61.4–76.6 % drain efficiency over the 100–1000 MHz band. The 2 × 2 inch compact power amplifier module combines four 30 W lossy matched broadband GaN HEMT PAs packaged in a ceramic SO8 package. Each of the 4 devices is fully matched to 50 Ohms and obtains 30.8–35.7 W with 68.6–79.6 % drain efficiency over the band. The packaged amplifiers contain a GaN on SiC device operating at 48V drain voltage, alongside GaAs integrated passive matching circuitry. The four devices are combined using a broadband low loss coaxial balun. We believe this combination of output power, bandwidth and efficiency is the best reported to date. These amplifiers are targeted for use in multi-band public mobile radios and for instrumentation applications.

Modeling of Spiral Inductors

Abstract: This section explains overview of the on-chip inductors. Demand for on-chip inductors has been increasing especially for CMOS RF circuits. An on-chip inductor is a key component because its performance directly affects the circuit performance and the chip cost. The onchip inductors have been used, for example, as a matching network component, as baluns, and as an inductive load. The requirements for on-chip inductors are to have an appropriate inductance value, high self-resonance frequency, and high-quality factor Q, and to occupy a small layout area. In this section, several types of on-chip inductors are introduced.

RF switchable balun

Abstract: A handheld communication device having an RF front end module has a switchable balun comprising a primary winding having a first two port winding and a second two port winding where a low noise amplifier is operatively coupled to the first and second two port windings and a power amplifier is operatively coupled to the first and second two port windings. A secondary winding is operatively coupled to an antenna, and a transceiver is operatively coupled to the low noise amplifier and the power amplifier. When the switchable balun is in a receive state, the antenna is operatively coupled to the transceiver through the low noise amplifier, and when the switchable balun is in a transmit state, the antenna is operatively coupled to the transceiver through the power amplifier. The ratio of the primary winding to the secondary winding is greater than a one-to-one ratio.

New Isolation Circuits of Compact Impedance-Transforming 3-dB Baluns for Theoretically Perfect Isolation and Matching

Abstract: New isolation circuits and design equations of compact impedance-transforming 3-dB baluns are suggested for theoretically perfect isolation and perfect matching at all ports. Any balun consists of two impedance transformers, being 180° out of phase, and an isolation circuit. For compactness, the impedance transformers need to be reduced and the isolation circuits should depend on phase delay of the compact impedance transformers. The compact balun with -90° phase delay of the compact impedance transformer is called the compact II-type balun and the one with non -90° phase delay is called the constant voltage-standing-wave-ratio type transmission-line impedance transformer (CVT) balun. Three isolation circuits are derived for the compact II-type baluns and five for the CVT baluns. Using the isolation circuits derived, the two types of compact baluns are fabricated and measured at a design center frequency of 1.5 GHz. The measured results have good agreement with prediction, showing power divisions of -2.9 and -3.3 dB (- 2.8 and -3.25 dB ), phase difference between two output signals of 181.8°(178.5°) , matching performance of -21.8, -31.8, and -33.8 dB ( -24, -22, and - 28 dB), and isolation of better than 40 dB (27 dB) for the compact II-type (CVT) balun.

A 160-GHz low-noise downconverter in a SiGe HBT technology

Abstract: A 160-GHz downconversion front-end for imaging arrays fabricated in a SiGe HBT technology is presented. The front-end features a fully differential architecture compatible with balanced on or off-chip antennas consisting of a three-stage LNA with 24 dB gain and Gilbert-cell mixer operating from −7dBm fundamental LO signal. The downconverter consumes 50 mA from a 3.3V supply and requires is 0.1 mm2 die area (excl. pads) per channel. With an 160-GHz input signal and an IF frequency of 150 MHz, the implemented front-end yields a 27-dB conversion gain and a 7.4-dB/9.5-dB (without/with auxiliary on-chip input balun) system noise figure.

Electrosurgical devices with balun structure for air exposure of antenna radiating section and method of directing energy to tissue using same

Abstract: An energy applicator for directing energy to tissue includes a feedline having an inner conductor, an outer conductor and a dielectric material disposed therebetween, and an antenna assembly having a radiating section operably coupled to the feedline. The energy applicator also includes a first balun structure configured to substantially confine energy to the radiating section when the energy applicator is energized and disposed in tissue, and a second balun structure configured to substantially prevent energy emitted from the radiating section from propagating proximal to the second balun structure along the feedline when the energy applicator is energized but not disposed in tissue.

Analysis and Synthesis of Double-Sided Parallel-Strip Transitions

Abstract: Antenna feeders, mixers, and filters made in double-sided parallel-strip technology usually must be adapted to unbalanced lines like the microstrip structure, needing transitions from asymmetric to symmetric waveguides (baluns). In this paper, we propose a new method for the evaluation of a generic tapered balun based on a conformal-mapping technique and an integral equation. This method, along with the use of an optimization technique such as genetic algorithms, allows for quick evaluation of the return losses of any tapered balun and the synthesizing of specific shapes to achieve desired responses in terms of return losses or impedance values.

Compact microstrip diplexer with differential outputs

Abstract: A novel microstrip diplexer with differential outputs that is designed using half-wavelength open-loop resonators is investigated. The proposed diplexer combines two functions, i.e. diplexing operation and a balun, into one circuit, resulting in a very compact module. The design method is elucidated, with a prototype demonstrated. Measurements were conducted to verify the theoretical prediction.

Compact transformer power combiners for millimeter-wave wireless applications

Abstract: Two current-summing transformer combiners for 60GHz-band power amplification in millimeter-wave wireless applications are characterized. The parasitic-compensated balun and fully-differential combiners mitigate imbalances caused by interwinding capacitance, while self-shielded output windings inhibit substrate coupling. Excellent agreement is seen between measurement and electromagnetic simulation. Power loss for both prototypes at 60GHz is ≪1.0dB and chip area is ≪0.015mm2. Reflected impedance uniformity between ports at 60GHz for the balun and fully-differential combiners is better than 2.4% and 4.5%, respectively. A lumped-element model for large-signal circuit design with ≪5.0% error in power loss and reflected port impedance across the 55–65GHz band is also described.