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.

A Planar Dual-Band Coupled-Line Balun With Impedance Transformation and High Isolation

Abstract: This paper proposes a novel planar dual-band coupled-line balun with impedance transformation and high isolation. Closed-form design equations are obtained based on the classical even-odd mode equivalent approach. For convenience of designing and synthesizing such a novel dual-band balun, the practical ranges of the frequency ratio, terminated impedances, and two free variables are provided under the conventional microstrip fabrication constraints. By adopting four coupled-line sections, six transmission-line stubs, and an isolation resistor, a microstrip prototype balun working at 1.0/2.6 GHz is designed, fabricated, and measured. There is a good agreement between the simulated and measured results. The wide bandwidths of 290 MHz from 0.83 to 1.12 GHz and 270 MHz from 2.44 to 2.71 GHz are obtained with the measured return losses (|S 11 |, |S 22 |, |S 33 |) and the isolation (|S 23 |) better than 10 dB, which effectively confirm the proposed theoretical predictions.

Design of Balanced Filtering Components Based on Isosceles Right-Angled Triangular Patch

Abstract: In this paper, a balanced bandpass filter (BPF), a balanced-to-balanced filtering power divider (FPD), and a balun filter are implemented using the isosceles right triangular patch element. Two isosceles right triangular patch elements are coupled through an open stub for a triple-mode passband response under differential-mode operation and wide common-mode suppression simultaneously. To further improve the selectivity, an open stub is loaded on each feed-line. Based on these elements, a balanced BPF with excellent performance can be implemented. As an extension, a balanced-to-balanced FPD and a balun BPF are implemented based on the structure of the filter. For validation of the proposed configurations, all the balanced BPF, FPD, and balun BPF have been fabricated and measured. All measured results are found to be in a reasonable agreement with the simulation results.

High permitivity dielectric microstrip dipole antenna

Abstract: A miniature microstrip dipole antenna is constructed on a high permitivity dielectric substrate for compactibility with microwave monolithic integrated circuit (MMIC) technology. The antenna comprises two dipole arms coupled to opposite faces of the substrate. The dipole arms are coupled to a microstrip transmission line through a tapered balun. The tapered balun comprises two conductors on opposite faces of the substrate which are coupled to corresponding dipole arms. The conductors are separated laterally (with respect to the width of the face of the substrate) a calculated distance, and are gradually tapered. This allows the balun to efficiently transform unbalanced signals at the microstrip transmission line to balanced signals at the plurality of dipole arms. Alternatively, the balun allows balanced signals at the dipole arms to be efficiently transformed to unbalanced signals at the microstrip transmission line. To achieve additional radiation directivity, a ground plane is coupled to and parallel with a back face of the substrate. By using a high dielectric substrate, the cavity formed between the substrate and the ground plane is relatively very shallow.

Stopband-Extended Balanced Filters Using Both λ/4 and λ/2 Sirs with Common-Mode Suppression and Improved Passband Selectivity

Abstract: Benefltting from the simultaneous utilization of quarter- wave (‚/4) and half-wave (‚/2) microstrip resonators, a via-free balanced bandpass fllter (BPF) with direct-coupled scheme is presented in this study. In the beginning, a single-ended fllter with transmission zeros (TZs) is newly proposed and the mechanism of creating two TZs around the passband without necessitating cross couplings is adopted. The TZs can be made structure-inherent based on the coexisted out-of-phase couplings among a coupled-resonator pair. On the foundation of the presented single-ended fllter, a balanced fllter featuring extended difierential-mode (DM) stopband, good common- mode (CM) suppression, and improved passband selectivity has been designed and implemented. The DM stopband extension is achieved by misaligning the higher-order harmonic frequencies of each resonator in the DM bisected circuit while the CM suppression is accomplished by both harmonic misalignment and careful designed coupled structure in the CM bisected circuit. Eventually, a demonstrated balanced fllter centering at 1.5GHz possesses DM stopband extended up to 8f d 0 , where f d 0 denotes the DM operation frequency, and its CM rejection ratio (CMRR) within DM passband better than 51.9dB is attained. For measurement convenience, the DM characterizations have been accomplished by 2-port network analyzer with simple rat-race baluns and are found relatively accurate within the i15dB bandwidth of the utilized baluns.

Lumped parameter balun

Abstract: A balun, which does not use magnetic coupling and is easily integrated in MMICs, is formed of lumped parameter inductive and capacitive circuit elements. In one embodiment, a termination circuit is utilized to prevent reflections of common mode signals.