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.

Balun bandpass filter based on multilayer substrate integrated waveguide power divider

Abstract: A compact multilayer substrate integrated waveguide (SIW) balun bandpass filter is proposed. A 180° reverse phase characteristic between the input/output ports can be easily achieved by the middle metal-ground of the SIW power divider. Four inductive posts are added to the multilayer SIW power divider to realise a passband. Good in-band balance performance (amplitude and phase imbalance are less than 0.35°dB and 2°) over the passband are achieved for the balun bandpass filter.

A Compact Microstrip Square-Loop Dual-Mode Balun-Bandpass Filter With Simultaneous Spurious Response Suppression and Differential Performance Improvement

Abstract: A microstrip balun-bandpass filter (BPF) using capacitively loaded square-loop dual-mode resonator is proposed; it realizes not only simultaneous size reduction and spurious response suppression in filtering but also overall good differential performance of the balun. The phase and amplitude imbalance improvements due to the loaded resonator are also studied and verified by a prototype balun-BPF operated at 2.55 GHz with 3.5% fractional bandwidth. The experimental results reveal that size reduction of 47% and spurious suppressions of 30 dB beyond 1.5 f0 are achieved as compared to that of the conventional structure. The loading effect of the prototype balun-BPF reports 180.8° and 0.97 dB as phase and amplitude imbalances at the operating frequency respectively.

A $K$ -Band Frequency Doubler With 35-dB Fundamental Rejection Based on Novel Transformer Balun in 0.13- $\mu \text{m}$ SiGe Technology

Abstract: A compact balanced frequency doubler with more than 35 dB odd-harmonic rejection and fractional bandwidth of 73% is presented in this letter. Wide bandwidth and high odd-harmonic suppression is achieved by adopting a new technique for the transformer balun design, resulting in a very low magnitude imbalance of 0.13 dB and a phase imbalance of 0.4° over 7–15 GHz. The balun performance is improved by offsetting the radius of the primary and secondary coils, which reduces the parasitic coupling capacitance. The input and output frequency ranges for the doubler are 7–15 GHz and 14–30 GHz respectively. The circuit was fabricated in 0.13- $\mu \text{m}$ SiGe technology. The chip size is 0.6 mm $\times \, 0.4$ mm.

Active Integrated Antenna Design Using a Contact-Less, Proximity Coupled, Differentially Fed Technique

Abstract: A novel contact-less, differential feeding technique suitable for integrated active antenna design is demonstrated. This technique utilizes an odd mode signal to generate fringing fields on either side of a microstrip gap under the antenna. This allows electromagnetic energy to be efficiently coupled from the transmission lines to the radiating antenna. In a balanced integrated antenna amplifier configuration, the proposed non-contact feeding method removes the need for any balun or power combining network. Hence in theory, a compact RF front-end design with lower losses can be realized. This feeding method has been successfully applied to the design of simple passive microstrip patch antennas and active integrated antennas (AIA). Simulated and measured results are also included to validate the proposed feeding concept and antenna designs. The performance of the proposed differential feeding technique on a simple microstrip patch antenna has been systematically studied. The study suggests that the proposed proximity method is broadband in nature, allowing antennas operating at different resonant frequencies to be swapped without the need to change the feed dimensions and without degrading the matching performance

Balun circuit for radio frequency coils in magnetic resonance systems

Abstract: A balun circuit arrangement for radio frequency (RF) coils in magnetic resonance (MR) systems. The balun circuit arrangement comprises a conductor having a length equal to a quarter wavelength at the tuned resonance frequency of the (RF) coil.