Topic
Balun
About: Balun is a research topic. Over the lifetime, 5375 publications have been published within this topic receiving 52256 citations. The topic is also known as: Telephone balance unit.
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TL;DR: In this paper, a multiple-arm, folded element design is presented that allows a dipole to exhibit a matched impedance and high radiation efficiency when it is very closely spaced to a perfect electric conductor (PEC) ground plane.
Abstract: A multiple-arm, folded element design is presented that allows a dipole to exhibit a matched impedance and high radiation efficiency when it is very closely spaced (<0.05/spl lambda/) to a perfect electric conductor (PEC) ground plane. Impedance matching and a balanced feed are implemented within the antenna structure so that an external matching network and balun are not required. A dipole element design that exhibits self-resonance, a 46 ohm feed point resistance and a radiation efficiency in excess of 90% is described for a spacing of 0.023/spl lambda/ above a PEC ground plane.
64 citations
03 Jul 2011
TL;DR: In this paper, Collins et al. developed a novel design for a decade bandwidth, dual-polarized balanced antipodal Vivaldi antenna (BAVA) array, which allows an ultra-thin array profile, and will minimize the number of transmit/receive (T/R) modules needed for high performance, multifunction phased arrays.
Abstract: Rockwell Collins has developed a novel design for a decade bandwidth, dual-polarized Balanced Antipodal Vivaldi Antenna (BAVA) array. The BAVA element height and the array lattice spacing are about λ/2 at the high frequency end of a grating-lobe free operating band. This allows an ultra-thin array profile, and will minimize the number (hence, cost) of transmit/receive (T/R) modules needed for high performance, multifunction phased arrays. The elements are fed directly by a 50Ω stripline. No matching network or balun circuitry is needed to achieve an active VSWR < 3∶1 across the entire bandwidth over wide scan volume. Although the design includes a ground plane, it provides a very low cross-polarization level due to its ultra-thin profile. The BAVA array produces below −25 dB cross-polarization at principal planes, and better than −17 dB at 45° scan-angles along the diagonal plane.
64 citations
TL;DR: In this article, a miniaturized printed dipole antenna with the V-shaped ground is proposed for radio frequency identification (RFID) readers operating at the frequency of 2.45 GHz.
Abstract: In this paper, a miniaturized printed dipole antenna with the V-shaped ground is proposed for radio frequency identification (RFID) readers operating at the frequency of 2.45 GHz. The principles of the microstrip balun and the printed dipole are analyzed and design considerations are formulated. Through extending and shaping the ground to reduce the coupling between the balun and the dipole, the antenna’s impedance bandwidth is broadened and the antenna’s radiation pattern is improved. The 3D finite difference time domain (FDTD) Electromagnetic simulations are carried out to evaluate the antenna’s performance. The effects of the extending angle and the position of the ground are investigated to obtain the optimized parameters. The antenna was fabricated and measured in a microwave anechoic chamber. The results show that the proposed antenna achieves a broader impedance bandwidth, a higher forward radiation gain and a stronger suppression to backward radiation compared with the one without such a ground.
63 citations
12 Sep 2007
TL;DR: An inductorless LNA with active balun is designed for multi-standard radio applications between 100 MHz and 6 GHz and achieves impedance matching, noise canceling and a well balanced output.
Abstract: An inductorless LNA with active balun is designed for multi-standard radio applications between 100 MHz and 6 GHz. It exploits a combination of a common gate stage and a common source stage with replica biasing to maximize balanced operation. The NF is designed to be around 3 dB by using the noise canceling technique. Its best performance is achieved between 300 MHz to 3.5 GHz with gain and phase errors below 0.3 dB and plusmn2 degrees, 15 dB gain, S11<-14 dB, IIP3=0 dBm and IIP2 higher than +20 dBm at a total power consumption of 21 mW. The circuit is fabricated in a baseline 65 nm CMOS process, with an active area of only 0.01 mm2. The circuit simultaneously achieves impedance matching, noise canceling and a well balanced output.
63 citations
TL;DR: In this paper, a dual-polarized patch antenna with low profile and wide bandwidth is presented, where the square patch, where a bow-tie slot is etched on, is excited by two different balance-to-unbalance feedings for dual polarization.
Abstract: In this letter, a dual-polarized patch antenna with low profile and wide bandwidth is presented. The square patch, where a bow-tie slot is etched on, is excited by two different balance-to-unbalance feedings for dual polarization. One of the polarizations is excited by the central-placed transition, which transfers the unbalanced microstripline feed to the balanced slot feed. The other polarization is excited by a differential feed network, which contains two capacitively coupled probe feeds. By adopting the two balanced feedings, high isolation and low cross polarization are achieved. A prototype of the proposed antenna is built and tested. Measured results show that the $ - $ 10-dB reflection coefficient bandwidth of the two polarizations is about 18.8%, with port isolation less than $ - $ 28.5 dB.
63 citations