Passive Balun Research Articles

Integration of miniaturized balun and low‐noise amplifier for single‐in differential‐out applications

AbstractA low‐noise module comprises a low‐noise amplifier and a new type of passive balun, which consists of two λ/8 broadside‐coupled lines and a short redundant line, is presented. The on‐chip balun is not only low lossy and compact size but also provides good amplitude and phase balances at output ports over a quite wide frequency range. The method of designing the new‐type balun fabricated with CMOS IC technology is proposed. An experimental prototype operated at K‐band was designed and fabricated with a commercial 0.18‐μm CMOS technology to verify the effectiveness of the proposed design method. The measured results show the single‐to‐differential gain is about 9 dB, the amplitude imbalance of the output ports is less than 1.0 dB associated with the phase difference of 181 ± 3° over the frequency range of 20–40 GHz. The area of the prototype including the RF probe pads is about 0.73 × 1.28 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2117–2121, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26987

Design of an ultra small passive balun in CMOS 65 nm technology for 60 GHz applications

In this paper a new procedure for the spiral Marchand balun design is shown and demonstrated. The size reduction for this component is fundamental to obtain a high level of integration for the radio frequency analog circuits. This work shows a micro-structure that, working as a balun, achieves good performance in phase and amplitude balance, while maintaining minimum size. These results were achieved by performing an accurate theoretical analysis followed by an electromagnetic simulation of the structure. A set of equations are proposed to describe the component behavior and the measurements show a strong agreement with the simulations confirming the quality of the design flow. The balun shows a maximum of 1.5 dB of insertion loss, with 0.1 dB of amplitude imbalance. The phase imbalance reach as a maximum of 7° at 65 GHz. The total occupied area of the balun remain below to 0.01 mm2.

Noise-Figure Measurement of Differential Amplifiers Using Nonideal Baluns

This paper analyzes the noise and gain measurement of microwave differential amplifiers using two passive baluns. A general model of the baluns is considered, including potential losses and phase/amplitude unbalances. This analysis allows de-embedding the actual gain and noise performance of the isolated amplifier by using single-ended measurements of the cascaded system and baluns. Finally, measured results from two amplifier prototypes are used to validate the theoretical principles.

Chip design of an UWB and high gain on-chip transformer receiver front-end

An ultra-wideband receiver front-end operating in 3.1–8.0 GHz frequency range is presented. The proposed front-end consists of on-chip transformer low-noise amplifier, passive balun, double-balanced mixer, and is fabricated in a TSMC 0.18 μm CMOS process with 1.8 V supply voltage. Measured results show that maximum conversion gain of 30.32 dB, noise figure less than 5.9 dB, input return loss (S11) smaller than −15.3 dB, input-referred third-order intercept point of −21.4 dBm, 1 dB compression point (P1 dB) of −30 dBm over the whole frequency range of interest are achieved. In addition, isolations of LO to RF and LO to IF are less than −57 dB and −27.8 dB, respectively, chip area including pads is only 0.985 mm2 and power dissipation is 36.88 mW. The realized front-end achieves the smallest chip area and the best merit of figure compared with previously reported front-ends. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1422–1427, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25956

Fully integrated 24 GHz differential active sub-harmonic mixer located in CMOS multi-layer Marchand baluns

A fully integrated active sub-harmonic mixer (SHM) located in two Marchand baluns is presented. The proposed circuit was designed at 24 GHz for industrial, scientific and medical (ISM) band applications and fabricated in a 0.13 µm complementary metal-oxide-semiconductor (CMOS) process. The proposed circuit layout is based on allocating the active SHM into square passive baluns to reduce the chip area without degrading performance. Two design approaches, one using a multi-layer and the other using compensated capacitors, were adopted in the CMOS Marchand baluns process to increase the coupling coefficient sufficiently and to minimise the required balun size. Additionally, the conversion gain was increased by using the current-bleeding scheme in the SHM. Moreover, a conversion gain of 3.8 dB was achieved in the designed circuit at a local oscillator (LO) input power of 5 dBm. Both radio frequency-intermediate frequency (IF) and LO-IF isolations were better than 28 dB. The proposed circuit not only has a higher conversion gain than other published mixers that are operated at millimetre-wave frequencies, but also has an innovative circuit layout.

Design and Implementation of Baluns at 60 GHz on LTCC

Passive structures for working frequencies at 60 GHz open up new dimensions for wireless broadband applications. The bandwidth available allows even faster data transfer. Thanks to the technology development and RF characterization of low-sintering glass-ceramics, 3D structures and low-cost production will be achievable. A detailed description of the design and the manufacturing of planar galvanically coupled and planar field coupled passive baluns, such as Marchand baluns, is given in this paper. Baluns are mostly built up with partly lumped elements, which are realized as embedded passives. This is currently not possible at the 60-GHz–range in thick-film technology. Electromagnetic 3D FEM simulations are therefore carried out in order to optimize and analyze baluns at 60 GHz. Several types of baluns were produced in low-temperature co-fired ceramic (LTCC). Due to the required pattern resolution (line width, 60 μm; minimum gap, 40 μm) a fine-line screen printing process as well as micro via punching (70 μm) are necessary. Printing tolerances and process-related dimensional stability are evaluated. In addition, material properties, such as permittivity, are investigated up to 67 GHz. With the help of asymmetrical test equipment, cascaded baluns in series are characterized. A symmetrical MMIC amplifier was mounted via flip-chip in order to demonstrate its performance in real applications. Gold-stud-bumping is used for this purpose. The stud bumps, which are 60 μm in diameter, were placed in a pitch of 100 μm.

A monolithic double-balanced direct conversion mixer with an integrated wideband passive balun

This paper presents the design and performance characteristics of a 20-40 GHz monolithic double-balanced direct conversion mixer implemented using InGaP/GaAs HBT process. The compact MMIC mixer makes use of a Gilbert-cell multiplier and utilizes a broadband monolithic passive balun that has been developed for MMIC applications. The new balun makes use of multidielectric layer structure to achieve a broadband performance in a simple coplanar configuration. A measured return loss better than 15 dB, with a maximum insertion loss of 4.5 dB including the 3-dB power splitting loss has been achieved over the band from 15 to 45 GHz. Operated as a downconverter mixer, the newly developed direct conversion mixer achieves a measured conversion gain of 16 dB given an RF signal at 30 GHz, LO drive of 5 dBm and a downconverted baseband signal at 10 MHz. The mixer IP3 occurs at an output power of 4 dBm while the IP2 occurs at an output power of 11 dBm.

An UTRA/FDD Direct-Downconversion Mixer in 0.25 μm CMOS

In this paper the design of a 2 GHz direct-downconversion mixer for a UTRA/FDD receiver is presented. The mixer is implemented using a standard low-cost 0.25 μm, single-poly, six-metal CMOS process. An on-chip passive balun is used to generate a balanced RF input signal. In-house optimized device models are used for both active and passive components to achieve a voltage conversion gain of 12.8 dB, an iIP2 of 25 dBm, an iIP3 of −3.1 dBm, and a noise figure of 8 dB. The circuit provides I and Q signal path outputs while drawing 6 mA from a 2.5 V supply.

2.4 GHz single-balanced diode mixer fabricated on Al2O3 substrate by thin-film technology

A passive balun using spiral inductors and interdigital capacitors has been developed for a 2.4 GHz balanced diode mixer on Al2O3 substrates. Using this passive balun on the input port (RF port and LO port) of a mixer circuit and incorporating the Schottky diode model, a wideband single-balanced diode mixer was designed, fabricated, and characterized © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 83–86, 2000.

Over-30-GHz limiting amplifier ICs with small phase deviation for optical communication systems

For a high-speed limiting amplifier with small phase deviation, a new design technique using a uniplanar passive balun and a narrow-band matching network is proposed. It is revealed that a device with small bias-dependence of parasitic capacitances, such as a high electron mobility transistor (HEMT), and a differential operation using passive baluns enables phase deviations at very high frequency to be reduced. Furthermore, suppressing harmonics can reduce phase deviation in a limiting amplifier, which operates in the highly nonlinear region. To verify these design techniques, two types of limiting amplifier ICs using an InP HEMT and AlGaAs/GaAs BCT technology were designed and fabricated. These IC's feature narrow-band matching circuits for input and output using transmission lines and uniplanar CPW-slot transition baluns for differential signals. The devices achieved high frequency operation of over 30 GHz with small phase deviations.

Broadband single- and double-balanced resistive HEMT monolithic mixers

A double-balanced (DB) 3-18 GHz and a single-balanced (SB) 2-16 GHz resistive HEMT monolithic mixer have been successfully developed. The DB mixer consists of a AlGaAs/InGaAs HEMT quad, an active LO balun, and two passive baluns for RF and IF. At 16 dBm LO power, this mixer achieves the conversion losses of 7.5-9 dB for 4-13 GHz RF and 7.5-11 dB for 3-18 GHz RF. The SB mixer consists of a pair of AlGaAs/InGaAs HEMT's, an active LO balun, a passive IF balun and a passive RF power divider. At 16 dBm LO power, this mixer achieves the conversion losses of 8-10 dB for 4-15 GHz RF and 8-11 dB for 2-16 GHz RF. The simulated conversion losses of both mixers are very much in agreement with the measured results. Also, the DB mixer achieves a third-order input intercept (IP/sub 3/) of +19.5 to +27.5 dBm for a 7-18 GHz RF and 1 GHz IF at a LO drive of 16 dBm while the SB mixer achieves an input IP/sub 3/ of +20 to +28.5 dBm for 2 to 16 GHz RF and 1 GHz IF at a 16 dBm LO power. The bandwidth of the RF and LO frequencies are approximately 6:1 for the DB mixer and 8:1 for the SB mixer. The DB mixer of this work is believed to be the first reported DB resistive HEMT MMIC mixer covering such a broad bandwidth. >

Broadband monolithic passive baluns and monolithic double-balanced mixer

The design and fabrication of four broadband monolithic passive baluns including CPW Marchand, multilayer MS Marchand, planar-transformer and broadside-coupled line baluns are presented. Operational frequencies range from 1.5 GHz to 24 GHz. Maximum relative bandwidths in excess of 3:1 are achieved. Simulated performances using full wave electromagnetic analysis are shown to agree with the measured results. Two accurate equivalent circuit models constructed from either electromagnetic simulated or measured S-parameters are developed for the MS Marchand and transformer baluns making the optimization of baluns and circuit design using the baluns much more efficient. The design of monolithic double-balanced diode mixer using two planar-transformer baluns is also presented. Without DC bias, the mixer shows a minimum conversion loss of 6 dB with the RF at 5 GHz and a LO drive of 15 dBm at 4 GHz. The measured input IP/sub 3/ of this mixer is better than 15 dBm over the 4 to 5.75 GHz frequency band. >