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.

Radiation Energy and Mutual Coupling Evaluation for Multimode MIMO Antenna Based on the Theory of Characteristic Mode

Abstract: This paper presents a novel method to evaluate radiation energy and mutual coupling in multimode antennas. Based on the theory of characteristics mode, how much each mode occupies the radiation and the mutual coupling from each feeding port is calculated with the modal energy occupied coefficients. Furthermore, the linear transformation of feeding network in multimode antenna system has been adopted to complete the modal-based method. Then, this method is utilized to analyze and decrease the mutual coupling between feeding ports. Hence, a hexagonal wideband antenna is proposed with its evolution process and measured to validate the proposed method. The presented hexagonal antenna is a four-port multimode antenna consisting a planar hexagonal plate, vertical tapered baluns, and feeding network at the ground plane. The whole antenna works in 3–6 GHz and all its four ports are well matched with high port-to-port isolation.

Printed BALUN circuits

Abstract: A planar BALUN circuit comprises two separate parallel branches with three capacitive elements. The values of the capacitive elements are selected to provide impedances which first of all enhance balanced current flow and which also impede and reduce unbalanced current flow. The circuit is provided so as to lie substantially in a single plane as a pattern disposed on a printed circuit board together with either certain discrete capacitive elements or with capacitive structures which are also printed on the board. The BALUN circuits of the present invention are particularly useful for circuits operating in the gigahertz range and are particularly useful in light weight devices such as cellular telephones and cellular telephone systems.

Development of low-loss broad-band planar baluns using multilayered organic thin films

Abstract: This paper presents the design and development of a low-loss and wide-band width multilayered Marchand balun. The balun has been implemented using printed circuit board materials with integrated multilayered organic thin films. We have designed the top layer transmission lines on twin-thickness organic thin films to achieve low loss and wide bandwidth for the balun. The experimental results demonstrate that the balun achieves less than 0.5-0.7 dB insertion loss throughout the 4-20-GHz operation bandwidth. The phase and amplitude imbalances are less than 5/spl deg/ and 0.5 dB, respectively. Time-domain measurement results demonstrate that the balun has negligible dispersion.

New Ultra-High-Isolation RF Switch Architecture and Its Use for a 10–38-GHz 0.18- $\mu$ m BiCMOS Ultra-Wideband Switch

Abstract: A new RF switch architecture with ultrahigh isolation and possible gain is proposed, analyzed, and demonstrated using 0.18-μm BiCMOS technology. The new RF switch architecture achieves an ultrahigh isolation through implementation of a new RF leaking cancellation technique in which the RF leaking signal is suppressed by combining with its replica using a balun. Its isolation is substantially higher than that produced by a conventional switch topology. An analysis of the new active balun employed in the proposed RF switch is also conducted, showing its distinguished characteristic of good balance across ultra-wide frequency ranges, making possible not only the achievement of extremely high isolation, but also ultra-wideband isolation for the RF switch. Additionally, the active balun also provides some gain to compensate for the inherent loss of the RF switch. The newly designed 0.18-μm BiCMOS RF switch exhibits an ultra-broadband performance from 10 to 38 GHz with - 2.6-dB loss to 0.4-dB gain, isolation from 40 to about 70 dB, and input return loss from 8 to 20 dB under small-signal conditions. Within 35.5-38.5 GHz, its isolation reaches extremely high values, with the highest isolation around 70 dB at 36 GHz, approaching the measurable limit of the vector network analyzer. Measured insertion loss and isolation under large-signal conditions at 35 GHz show around 1-2 and 51.5 dB, respectively. The RF switch consumes a dc current of only 8 mA from a 1.8-V source. The extremely high isolation achievable by the new RF switch demonstrates the possibility of pushing RF system performance limited by switch isolation to a next level.

Compact Millimeter-Wave Endfire Dual-Polarized Antenna Array for Low-Cost Multibeam Applications

Abstract: A compact multibeam endfire dual-polarized antenna array for low-cost millimeter-wave (mmWave) applications is proposed in this letter. Multimode substrate-integrated waveguide (SIW) section with interactions is applied as the basic beamformer. The dual-mode SIW is used in the beamforming network to support dual-polarization application without occupying an extra area. The printed dipole antenna with integrated balun and the open-ended SIW antenna with metallic strips are integrated to realize an endfire dual-polarized antenna element. Based on this endfire antenna element, a multibeam dual-polarized antenna array is developed. The proposed antenna array includes a four-element antenna array, an SIW beamforming network, and transitions. Additional air gaps between antenna elements are designed for mutual coupling reduction. The fabricated multibeam endfire dual-polarized antenna array achieves an impedance bandwidth of 11.3%, and the overlapped 3 dB beamwidth of the four generated beams in two polarizations are able to cover a wide range between ± 41°. The proposed low-cost multibeam antenna array can be a good candidate for 5G mmWave wireless applications.