Showing papers on "Balun published in 2006"

The eleven antenna: a compact low-profile decade bandwidth dual polarized feed for reflector antennas

Abstract: A novel dual polarized ultrawide-band (UWB) feed with a decade bandwidth is presented for use in both single and dual reflector antennas. The feed has nearly constant beam width and 11 dBi directivity over at least a decade bandwidth. The feed gives an aperture efficiency of the reflector of 66% or better over a decade bandwidth when the subtended angle toward the sub or main reflector is about 53/spl deg/, and an overall efficiency better than 47% including mismatch. The return loss is better than 5 dB over a decade bandwidth. The calculated results have been verified with measurements on a linearly polarized lab model. The feed has no balun as it is intended to be integrated with an active 180/spl deg/ balun and receiver. The feed is referred to as the Eleven antenna because its basic configuration is two parallel dipoles 0.5 wavelengths apart and because it can be used over more than a decade bandwidth with 11 dBi directivity. We also believe that 11 dB return loss is achievable in the near future.

Simple broadband measurements of balanced loads using a network analyzer

Abstract: This paper presents a simple broadband network analyzer technique for measuring balanced loads, such as antennas, without a balun. The technique uses the normal two-port calibration of the network analyzer, which is extended by the addition of two short lengths of cable. From the measured data, a circuit model of the antenna impedances can be found, and both the balanced and unbalanced impedances are readily extracted. Measured and computed data are presented and compared.

Inductively Compensated Parallel Coupled Microstrip Lines and Their Applications

Abstract: A simple method using lumped inductors to compensate unequal even- and odd-mode phase velocities in parallel coupled microstrip lines is presented. The singly and doubly compensated cases are analyzed to enable the optimum inductor values and the electrical lengths of the compensated coupled lines to be calculated from closed-form expressions. The technique proposed not only improves the performance, but also yields a more compact design. To demonstrate the technique's broad range of applicability, the compensated coupled-line structure is used to enhance the performance of a 900-MHz Lange coupler, a 1-GHz multisection 10-dB coupler, a 900-MHz planar Marchand balun, and a 1.8-GHz parallel coupled bandpass filter

Wide-band microstrip-to-coplanar stripline/slotline transitions

Abstract: Wide-band microstrip line to coplanar stripline (CPS) transitions are proposed. The transition consists of a multisection matching transformer and a quarter-wavelength radial stub for the impedance matching and field matching between the microstrip line and CPS, respectively. The proposed planar transition has the advantages of compact size, wide bandwidth, and straightforward design procedure. Several parameters are studied through simulations and experiments to derive some design guidelines. With the return loss of better than 14 dB, the 1- and 3-dB back-to-back insertion loss bandwidth can cover from 1.4 to 6.6 GHz (1 : 4.7) and from 1.1 to 10.5 GHz (1 : 9.6), respectively. In addition, the microstrip-to-CPS transition is extended to design a microstrip-to-slotline transition by tapering the CPS into a slotline. From 2.7 to 10.4 GHz (1 : 3.85), the back-to-back return loss is better than 15 dB and the insertion loss is less than 3 dB.

A 9-50-GHz Gilbert-cell down-conversion mixer in 0.13-/spl mu/m CMOS technology

Abstract: A broadband microwave/millimeter-wave (MMW) Gilbert-cellmixer using standard 1P8M 0.13-/spl mu/m complementary metal oxide semiconductor (CMOS) technology is presented in this letter. Two radio frequency (RF) transformer baluns are used in RF-and local oscillator (LO)-ports to convert single-ended signals to differential signals. Thin film microstrip line is employed for the matching networks and transformer design. This mixer has a conversion gain of better than 5dB from 9 to 50GHz. Between 5 and 50GHz,the RF- and LO-to-intermediate frequency (IF) isolations are better than 40dB. The RF-to-LO and LO-to-RF isolations are all better than 20dB. To the authors' knowledge, this is the first CMOS Gilbert-cell mixer operating to MMW frequency to date.

An LTCC balanced-to-unbalanced extracted-pole bandpass filter with complex load

Abstract: In this paper, the fundamental characteristics of a novel third-order RF balanced-to-unbalanced filter, namely, a balun filter, for integrated RF module applications are presented. This center-tapped transformer-based new device works concurrently as a balun, an extracted-pole bandpass filter, and a matching network. As coupled resonant tanks are employed to perform the balun type of operation, traditional coupled-resonator filter theory can thus be used to design and analyze such a new device. Moreover, an extracted-pole technique is used not only for creating a transmission zero, but also provides a capability to match the filter with a complex load. In addition to providing a simple design procedure for the device, its working mechanism is also revealed mathematically. Specifically, return-loss sensitivity with respect to each resonator admittance and complex load matching capability are discussed in details. This balun filter has been implemented in a multilayered low-temperature co-fired ceramic substrate, demonstrating its promising potentials in miniaturized RF front-end modules. Experimental measurements are also presented to validate the theory and computer simulations.

A $+$ 31.5 dBm CMOS RF Doherty Power Amplifier for Wireless Communications

Abstract: A fully differential Doherty power amplifier (PA) is implemented in a 0.13-mum CMOS technology. The prototype achieves a maximum output power of +31.5 dBm with a peak power-added efficiency (PAE) of 36% (39% drain efficiency) with a GMSK modulated signal. The PAE is kept above 18% over a 10 dB range of output power. With a GSM/EDGE input signal, the measured peak output power while still meeting the GSM/EDGE mask and error vector magnitude (EVM) requirements is +25dBm with a peak PAE of 13% (PAE is 6% at 12 dB back-off). Instead of using a bulky lambda/4 transmission line, a passive impedance inverter is implemented as a compact lumped-element network. All circuit components are fully integrated on a single CMOS die except for an off-chip capacitor for output matching and baluns. The die size is 2.8times3.2mm2 including all pads and bypass capacitors

Monolithic Broadband Gilbert Micromixer With an Integrated Marchand Balun Using Standard Silicon IC Process

Abstract: A single-ended wideband downconversion Gilbert micromixer is demonstrated in this paper using 0.35-mum SiGe BiCMOS technology. A transimpedance amplifier with resistive feedback is utilized in the IF stage while a broadband Marchand balun is employed to generate wideband differential local oscillator signals. The planar Marchand balun topology employed in this paper can generate truly balanced signals even in the presence of the lossy low-resistivity (~10 Omegamiddotcm) silicon substrate. A systematic approach to measure the frequency response of each individual stage in a Gilbert mixer is developed in this paper. This single-ended wideband mixer has the conversion gain of 15 dB, IP1dB of -19 dBm, IIP3 of -7 dBm, and the noise figure of 13 dB. The mixer works from 3.5 to 14.5 GHz

Vivaldi Antennas for Microwave Imaging: Theoretical Analysis and Design Considerations

Abstract: The geometrical and electrical features of the Vivaldi antenna are studied in the light of the frequency-independent antenna theory. A scaling principle is derived for the exponential tapering of the antenna, and a closed-form model for the current distribution is provided. Such theoretical results are in good agreement with several numerical simulations performed by using the NEC2 code. Furthermore, a practical feeding system, based on a double-Y balun, is developed and tested to obtain a more systematic approach to the design of the aforesaid antennas

Dielectrically Transduced Single-Ended to Differential MEMS Filter

Abstract: A single-ended input to balanced output 425MHz mechanically coupled electromechanical filter is presented. This technology provides 1MHz channel select filtering while eliminating the need for RF switches and baluns in front-end transceivers. The filter achieves 8dB insertion loss with -50dB stop-band rejection and -48dB common-mode suppression

A single-chip linear CMOS power amplifier for 2.4 GHz WLAN

Abstract: A single-chip linear CMOS PA for OFDM WLAN applications adopts a fully differential topology with transformer-type output matching and operates from a 3.3V supply. All of the components, including the input balun and output transformer, are integrated on a single 0.18mum CMOS die and no off-chip component is required

Finite-volume time-domain analysis of a cavity-backed Archimedean spiral antenna

Abstract: This paper presents a comprehensive analysis of a broadband (2-18 GHz) cavity-backed Archimedean spiral antenna. The simulation of the device is performed using the finite-volume time-domain method. The high geometrical flexibility of this method permits a detailed modeling of the antenna including the thin substrate, the feeding balun, and the cavity loaded with a honeycomb absorber. The simulated far-field radiation patterns and the return loss are compared to measurements, showing an excellent agreement over the whole frequency band. The radiation mechanism of the spiral is visualized by observing the current distribution on the spiral arms for both pulsed and harmonic excitation modes

A 1.2V, 60-GHz radio receiver with on-chip transformers and inductors in 90-nm CMOS

Abstract: This paper describes an integrated 60-GHz receiver in 90-nm CMOS including an LNA and downconversion mixer as well as LO and IF buffers. Transformer baluns are used for S/D conversion of the RF and LO signals to allow for conventional double-balanced mixing. The single-ended downconversion gain of a 60 GHz signal to a 5 GHz IF is 16 dB with an input compression point of-21 dBm while consuming 60 mW of power. The DSB noise figure is below 7 dB over the entire IF bandwidth which is greater than 1 GHz. The use of spiral inductors and transformers as matching elements resulted in a die area of only 600 mum times 475 mum including pads

A multiband CMOS RF front-end for 4G WiMAX and WLAN applications

Abstract: In this paper, we present the design and implementation of the RF front-end for the WiMAX (802.16e) and WLAN (802.11n) standards. The front-end covers the frequency ranges of operation for licensed and unlicensed bands of WiMAX and WLAN, which include 2.3 GHz - 2.9 GHz, 3.3 GHz - 3.7 GHz and 4.9 GHz - 5.9 GHz. The gain of the front-end is between 30 - 32 dB for all the bands while achieving noise figures of 2.5 dB, 3.5 dB and 5.9 dB at the center frequencies of the lower, middle and upper bands respectively. The total front-end operates at the bias current of 26.25 mA and consumes 48 mW of power. The components include in the front-end are low noise amplifier, active balun or single to differential converter and mixer. The design of the front-end is performed in 1.8 V IBM CMOS 0.18/spl mu/m process.

A highly linear SiGe double-balanced mixer for 77 GHz automotive radar applications

Abstract: An active double-balanced mixer for automotive applications in the 77 GHz range is presented. The circuit includes on-chip baluns both at the RF and the LO port. The mixer was designed and fabricated in a 200 GHz f/sub T/ SiGe:C bipolar technology. The chip was characterized by on-wafer measurements. At 77 GHz, the conversion gain of the mixer is 11.5 dB. The single sideband noise figure at 77 GHz is 15.8 dB. The input-referred 1 dB compression point at 75 GHz is -0.3 dBm. Measurements across the wafer verified that this mixer circuit is robust against wafer inhomogeneities. The size of the chip is 700/spl mu/m /spl times/ 900/spl mu/m. The circuit was designed for a supply voltage of 5.5 V and draws 75 mA.

A novel LTCC miniaturized dualband balun

Abstract: In this letter, a novel low temperature cofired ceramic (LTCC) miniaturized dualband balun using a tapered line structure has been presented. The key concept for our dualband solution is by employing tapered line structures in the conventional Marchand baluns. In our new design, we have demonstrated the tapered line structure can shift the periodic operation frequency to a desired frequency band. A sample balun design has been presented. The novel LTCC dualband balun has been simulated and verified by measurement. The measured results exhibit that the proposed balun can easily cover the important radio frequency bands at 2.4GHz, 5.25GHz, and 5.85GHz.

Bandwidth and gain improvement of a circularly polarized dual-rhombic loop antenna

Abstract: We present a novel way to improve the performance of a circularly polarized (CP) dual-rhombic loop antenna. The bandwidth is enhanced by adding a pair of parasitic rhombic loops inside the dual-rhombic loop while the gain is increased with the help of a short backfire antenna (SBA). Good impedance matching is obtained by introducing a broadband balun. The addition of the parasitic elements leads to a bandwidth of 46% for $ axial ~ratio ~( AR) leq 2~ dB$ with an impedance bandwidth of 50% for $ VSWRleq 2$. The dual-rhombic loop excited SBA achieves an AR ( $leq 3~ dB$ ) bandwidth of 45% with an antenna gain of 11 dBi.

Low power 8-GHz ultra-wideband active balun

Abstract: A new low-power CMOS active balun is designed for ultra-wideband applications, using a pair of common-source NMOS and common-gate PMOS transistors. This balun gives an impedance transformation ratio of 1:2. Without compensation feedback, the circuit provides a differential signal within 2dB and 3/spl deg/ of gain and phase imbalance, respectively, up to 8-GHz. Total power consumption is only 1.44 mW at the supply voltage of Vdd=1.2V, much less than 12 mW of the traditional active balun. This saves 88% of power. The circuit can be fully integrated in RFIC for low power and low cost.

Ultra Low Profile Dipole Antenna with a Simplified Feeding Structure and a Parasitic Element

Abstract: This study is devoted to a half-wave dipole with a conductor plane at a distance much smaller than a quarter wavelength which we designate as an ultra low profile dipole (ULPD) antenna in this paper. The concerns of ULPD antenna are the feeding method and the impedance matching, because the input impedance usually tends to be lowered by the existence of a metallic structure in its proximity. In this paper, we propose a ULPD antenna with an excellent impedance matching and a coaxial feed built within the antenna structure so that the external matching and a balun are not required. A coaxial cable is used as a feed line and extended to be a half of a half wavelength dipole. The other half is made up of a parasitic element, which is connected to the outer conductor of the coaxial radiator. To make a matching, the outer conductor of the coaxial radiator is stripped off at a suitable length, and the total length of a dipole is considered for its resonance at a desired frequency of 2 GHz. The experiment has been conducted. The results show the return loss of -27 dB and the maximum gain of 9 dBi in the normal direction to the conductor plane. The computational results are also obtained, which agree well with the experimental results.

Fully-integrated multi-standard VCOs with switched LC tank and power controlled by body voltage in 130nm CMOS/SOI

Abstract: In this paper, the design of two VCOs for wireless multi-standard applications is presented. These circuits have been produced using CMOS/SOI technology, with body voltage to control power consumption and phase noise performance. A new architecture for multi-standard applications is proposed. To our knowledge, this is the first structure using a balun to change the oscillation frequency and the body biasing to control VCO core current. Four standards are covered by these structures: GSM (900MHz), DCS (1.8GHz), Bluetooth (2 GHz) and 802.11a (0.8GHz). The tuning range can vary from 80 MHz to 0.8GHz by using frequency divider, adjusted varactor and switched LC tank. The main idea is to use only two MOS varactors to cover the entire frequency span. The first one is needed to get the matched frequency variation and the second to adjust the oscillation frequency. Such VCOs can be made thanks to CMOS/SOI technology advantages, high-Q passives and body voltage biasing that allow current control and switched LC tank. At a frequency offset of 100kHz, the single side band phase noise measurements were -82dBc/Hz and -102dBc/Hz at 0.2GHz and 1.8GHz respectively.

Broadband circularly polarized rectangular loop antenna with impedance matching

Abstract: A broadband circularly polarized rectangular loop antenna is developed. The broadband performance is achieved by adding a pair of parasitic loops inside the rectangular loop. Good impedance matching is obtained by introducing a broadband balun. The proposed rectangular loop has a bandwidth of 46% for axial ratioles2dB and 50% for VSWRles2 with a gain of around 8dBi

65-GHz receiver in SiGe BiCMOS using monolithic inductors and transformers

Abstract: This paper describes a single-chip 65-GHz SiGe BiCMOS radio receiver IC which includes an LNA, a transformer balun, a downconversion mixer, an IF amplifier, and a 65-GHz VCO. The single-ended downconversion gain is 21 dB with an input compression point of -22 dBm. The DSB receiver noise figure is a record 12 dB for IF frequencies in the 0 to 2 GHz range. By employing only transformers and inductors as matching elements, the die area, which includes all pads, is 790 /spl mu/m /spl times/ 740 /spl mu/m.

Integrated capacitor shield for balun in MRI receivers

Abstract: A balun is included in a magnetic resonance imaging system. The balun conditions electromagnetic signals received from at least one RF receiver coil. The balun includes a balun shield having an integrated capacitor therein. The balun shield blocks unwanted feedback from effecting performance of any components contained within the balun shield.

High- $Q$ Above-IC Inductors Using Thin-Film Wafer-Level Packaging Technology Demonstrated on 90-nm RF-CMOS 5-GHz VCO and 24-GHz LNA

Abstract: High-Q inductors are important for the realization of high-performance, low-power RF-circuits. In this paper, on-chip inductors with Q-factors above 40 have been realized above the passivation of a 90-nm RF-CMOS process using wafer-level packaging (WLP) techniques . The influence of a patterned polysilicon and metal ground shield on the inductor-Q is compared and the influence of highly doped active area underneath the inductors is shown. A 5-15 GHz above-IC balun has been realized on 20 Omegamiddotcm silicon with the use of patterned ground shield. The technology is demonstrated by a low-power 90-nm RF-CMOS 5-GHz VCO with a core current consumption of only 150 muA with a 1.2-V supply, and a 10% tuning range with a worst case phase noise of -111 dBc/Hz at 1-MHz offset. A 24-GHz single-stage common-source low-noise amplifier has been realized, with a noise figure of 3.2 dB, a gain of 7.5 dB, and a low power consumption of 10.6 mW

Development of three models of the eleven antenna: A new decade bandwidth high performance feed for reflectors

Abstract: The Eleven antenna is a novel dual polarized ultra wide band (UWB) feed with a decade bandwidth for use in both single and dual reflector antennas. The special name is associated with its basic 11 iquest configuration of two parallel dipoles with 0.5 wavelengths spacing, and because it can be used over more than a decade bandwidth (and 11 > 10 iquest) with 11 dBi iquest directivity by making the dipoles log-periodic. The phase center has a constant location in the ground plane, so a high aperture efficiency of the reflector of 66% or better is available over the whole band. The return loss is better than 5 dB, but we believe that it is possible to achieve 11 dB iquest. The feed has no balun as it is intended to be used with an active 180 deg balun and receiver. The Eleven antenna is about 11 times smaller iquest than alternative end-fire log-periodic feeds.

A 800- to 3200-MHz Wideband CPW Balun Using Multistage Wilkinson Structure

Abstract: A novel ultra-wide band CPW (coplanar waveguide) balun having the structure of multistage Wilkinson power divider is proposed. It has an 180deg phase inverting structure between signal line and ground planes of CPW transmission line. The 3-stage Wilkinson power divider is transformed directly into the ultra-wide band balun without any cost of the size and performances. The measurement shows the right S-parameters as a power divider and the proper out of phase as a balun. The measured amplitude and phase unbalances at output ports are plusmn 0.5dB and plusmn 6deg, respectively over 800~3200MHz, while the maximum insertion loss is 0.8dB

Integrated transformer baluns for RF low noise and power amplifiers

Abstract: On-chip transformer baluns integrated with an RF front-end architecture for medium power WLAN is presented. Method of measuring and characterizing a 3-port balun with a 2-port network analyzer is discussed. Implemented in 0.18/spl mu/m CMOS, the receive path including a switch, an input transformer and a differential LNA, achieves S/sub 21/ of 17dB, NF of 4.1dB, and IIP3 of 0dBm at 2.45GHz; the transmit path of a differential PA with an output transformer, achieves P/sub sat/ of 21dBm, P/sub 1dB/ of 17dBm, and max PAE of 21%.

Multilayer planar balun transformer, mixers and amplifiers

Abstract: A surface mountable transformer integratable into a printed circuit board. In one aspect, the transformer (300) comprises two broadside vertically coupled transmission lines (304,308,312,316). In another aspect, the transformer may comprise two broadside vertically partially coupled transmission lines. The layout of the transformer is adaptable for use in microwave modules where transformers are integrated into the printed circuit board and the active components are mounted in the cavity. The layout preferably requires only two signal areas. In addition, an aspect of the present invention allows the differential or unbalanced ports to lie on the same surface as the balanced port.

A compact LTCC bluetooth system module with an integrated antenna

Abstract: In this article, a system-on-package (SoP) approach for Bluetooth system module applications using low-temperature co-fired ceramic (LTCC) technology is presented. The developed LTCC integrated substrate for our Bluetooth module application is overall 12 × 12 × 1 mm3 in size, with integration of two originally proposed components, a balanced-to-unbalanced bandpass filter and a folded meander-line inverted-F antenna, as well as other passive circuitries. The embedded balanced-to-unbalanced filter, which is derived from the basic center-tapped transformer circuit, works simultaneously as a balun and a bandpass filter, thus leading to a significant amount of size reduction for the overall module. Likewise, comparing to the usual quarter-wavelength inverted-F antennas, our proposed antenna is only one-tenth of a wavelength in length—but no sacrificing of antenna efficiency. Consequently, couplings among different functional blocks of this highly integrated module are crucial to its performance and the resulting effects are discussed. A fully functional prototype is successfully fabricated and tested, demonstrating a promising solution for Bluetooth applications. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.

Design of new three-line balun and its implementation using multilayer configuration

Abstract: This paper proposes a new balun that is composed of three coupled quarter-wavelength lines. The proposed balun is optimized by using design of experiments to achieve a maximum bandwidth. After the optimization, it is transformed into the balun consisting of a pair of coupled quarter-wavelength lines in connection with an uncoupled quarter-wavelength line. The design method and its implemented results using a multilayer configuration are presented. It is shown that this new balun can be made more compact, providing good performances over the wide frequency range. Therefore, the balun developed here is applicable to many wireless and mobile communication systems. The design equation for a given set of balun impedances at unbalanced and balanced ports is derived from an equivalent circuit of the proposed balun. To demonstrate the feasibility and validity of the design equation, the size 2012 multilayer ceramic chip baluns with three different balun impedances, which operated in the 2.4-GHz industrial-scientific-medical band frequency, are designed and fabricated by the use of low-temperature co-fired ceramic technology. According to the measured results, the maximum insertion loss is 0.81 dB, the maximum in-band phase imbalance is within 7/spl deg/, and the maximum in-band amplitude imbalance is less than 0.7 dB.