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 0.5–6 GHz 360° vector-sum phase shifter in 0.13-µm CMOS

Abstract: A 05-6 GHz CMOS vector-sum phase shifter with a full 360° phase range is presented Employing phase-reversible variable gain amplifiers (VGAs), for simultaneous amplitude and polarity control, the phase shifter realizes a continuously tunable phase shift of 360° with only one DC control voltage and single-ended I- and Q-signals A maximum gain of 11 dB is measured with a 2-dB gain variation over the 05-6 GHz band The root-mean-square (RMS) amplitude and phase error are less than 095 dB and 7° The measured in-band noise figure (NF) is better than 13 dB Wideband input and output matching are also achieved throughout the entire band Operating at 15 V, the entire circuit consumes 275 mW To the best of the authors' knowledge, it is the first time the phase-reversible VGA is used to realize a full-360° vector sum phase shifter, which eliminates the need for an input balun and a complicated control circuit

Design of a New Type Planar Balun by Using Trans-Directional Couplers

Abstract: This paper presents a new type of planar balun implemented by trans-directional (TRD) couplers. The formulation of the proposed balun is derived and the characteristics of the balun are analyzed. This balun requires no via-hole connection to ground. Thus, the phase errors caused by the inductive effect of via-holes are reduced. The configuration of TRD couplers also helps to reduce the complexity of dc biasing of active circuits in the next stage. Two prototypes are designed and built to verify the design concept. The first one, operated from 1.94 to 2.69 GHz, is realized by 3-dB TRD couplers. The second prototype, which is operated from 376 to 458 MHz, is constructed by two 4.8-dB TRD couplers. The dimension of this prototype is only 16.8 mm × 39.4 mm. This small area is achieved by meandering the coupled-line sections because its coupling effect is purely contributed by periodical shunt capacitors on the microstrip lines. Measured results are in good agreement with simulated results.

A Broadband Dual Circularly Polarized Conical Four-Arm Sinuous Antenna

Abstract: A novel wideband four-arm sinuous antenna with dual circular polarizations (CPs) and unidirectional radiation is proposed. Different from the conventional designs, this sinuous antenna is realized in a conical form and no ground plane or absorptive cavity is required to obtain unidirectional radiation. The beamforming network for dual circularly polarized operations consists of a wideband quadrature coupler and two wideband baluns, and an auxiliary feeding patch is introduced to facilitate the connection between baluns and sinuous arms. The design of baluns and coupler is inspired from the printed exponentially tapered microstrip balun and broadside-coupled microstrip coupler, respectively. The dynamic differential evolution algorithm is employed to optimize the geometry of coupler for optimal performance. For both polarizations, the presented antenna has wide impedance bandwidth, good axial ratio, moderate realized gain, and front-to-back ratio within 2–5 GHz. An antenna prototype is fabricated and tested. The agreement between simulation and measurement results validates the proposed antenna framework. The demonstrated antenna has advantages of wide bandwidth, dual CPs, unidirectional radiation, lightweight, and low cost, and is promising for applications in wireless systems.

A Wide-Band Transformer from an Unbalanced to a Balanced Line

Abstract: The frequency characteristic of a particular type of "balun" (a transformer from an unbalanced to a balanced line) is discussed, and it is shown that by inserting a properly designed pair of quarter-wave sections to match the balun to the balanced line of higher characteristic impedance, the standing-wave ratio can be kept below 1.25 over frequency bands of the order of 4 to 1. Design parameters are given for the case of 128-ohm and 150-ohm balanced lines, for a 50-ohm unbalanced line.

Radio frequency antenna

Abstract: A quadrifiliar radio frequency antenna intended primarily for the reception of circularly polarised transmissions has the helical antenna elements (10A - 10D) deposited upon a dielectric material of high dielectric constant and of cylindrical form (13). Within the cylinder is contained the means whereby the signals received by the said elements are transformed to a form more suitable for further processing eg. a split tube balun (see Fig. 2 not shown). This is achieved by depositing conductors upon a dielectric material of high dielectric constant and of cylindrical form (22), co-axial with (13). Around the cylinder (13) if a further cylinder (19) which provides a means of varying the operating frequency. The interconnection of the parts into a rigid single assembly is to be achieved by a single soldering operation. The results in a smaller than could be achieved using prior art. The antenna is especially useful for GPS reception.