Conventional Marchand Balun Research Articles

An Ultraminiaturized Bandpass Filtering Marchand Balun Chip With Spiral Coupled Lines Based on GaAs Integrated Passive Device Technology

The integrated passive device (IPD) technology has become a new research hotspot, and it depends on electrical characteristics of GaAs, NiCr, and Si3N4 to construct radio frequency (RF) components. RF elements constructed by the IPD technology have features of high quality and ultra-small size, especially for capacitors and inductors. In order to realize the miniaturization of RF circuits, dimensions become as small as possible. Consequently, the layout of a spiral coupled line (SCL) cannot be drawn freely, so that it has uncontrollable odd- and even-mode impedances and a large coupling coefficient, which may limit the design of the traditional Marchand balun negatively. This article solves this problem by designing a GaAs IPD Marchand balun with 1/8-wavelength coupled lines (CLs) and using a capacitor termination to replace the open end in the conventional Marchand balun. Meanwhile, a filter is added to realize a filtering function. The proposed bandpass filtering Marchand balun (BFMB) chip has a size of 1.49 mm $\times1.39$ mm, and measured results indicate that it has an operation band of 2.39–5.68 GHz with a phase imbalance of 5.26° and a magnitude imbalance of less than 0.35 dB.

A Miniaturized Marchand Balun Model With Short-End and Capacitive Feeding

A new equivalent circuit model of an electrical size-reduced coupled line radio frequency Marchand balun is proposed and investigated in this paper. It consists of two parts of coupled lines with significantly reduced electrical length. Compared with the conventional Marchand balun, a short-circuit ending is applied instead of the open-circuit ending, and a capacitive feeding is introduced. The electrical length of the proposed balun is reduced to around 1/3 compared with that of the conventional Marchand balun. Detailed mathematical analysis for this design is included in this paper. Groups of circuit simulation results are shown to verify the conclusions. A sample balun is fabricated in microstrip line type on the Teflon substrate, with low dielectric constant of 2.54. It has a dimension of $0.189\lambda _{g} \times 0.066 \lambda _{g}$ with amplitude imbalance of 0.1 dB and phase imbalance of 179.09° ± 0.14°. The simulation and experiment results are in good agreement.

A W-Band Power Amplifier Utilizing a Miniaturized Marchand Balun Combiner

A miniaturized Marchand balun combiner is proposed for a W-band power amplifier (PA). The proposed combiner reduces the electrical length of the transmission lines (transmission line) from about 80 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> to 30 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> , when compared with a conventional Marchand balun combiner. Implemented in a 1-V 65-nm CMOS process, the presented PA achieves a measured saturated output power of 11.9 dBm and a peak power-added efficiency of 9.0% at 87 GHz. The total chip area (with pads) is 0.77×0.48 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , where the size of the balun combiner is only 0.36×0.13 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

THE MINIATURE FREQUENCY DOUBLER USING COMPENSATED CAPACITIVE LINE IN BALUN

A compact balanced frequency MMIC doubler using compensated capacitive line in Marchand balun is proposed. With multi-coupled lines technology, the balun is applied to a balanced doubler successfully. Compared with the conventional Marchand balun, more than 55% reduction in the length of coupled line can be achieved. Implemented by a PHEMT process, the compact monolithic balanced frequency doubler with better performance can be obtained. An operation bandwidth from 20 to 44GHz with the best conversion loss of 8.4dB at 25GHz can be achieved. In addition, the fundamental frequency suppression is better than 28.9dB, and the chip dimension is as small as 0:41 £ 0:68mm 2 .

A COMPACT BALUN BASED ON MICROSTRIP EBG CELL AND INTERDIGITAL CAPACITOR

A novel compact balun (balanced-to-unbalanced) that consists of a low-pass network served by a microstrip electromagnetic bandgap (EBG) cell and a high-pass …-network formed with an interdigital capacitor is presented. This proposed approach can efiectively operate the compact balun without the use of ‚=4 microstrip lines to reduce the circuit area over 50% compared to the conventional Marchand balun. The core dimension of the compact balun is 0:74cm£0:7cm. The planar structure enables an e-cient circuit design in printed circuit boards (PCB) without using any bonding wires, defected ground structures (DGS), or surface mounted devices (SMD). A compact balun operating in the 3GHz band has been implemented in a FR-4 PCB. From the measured results, the return loss of the input port is better than 15dB over the band from 2.6 to 4GHz. The amplitude and phase imbalances are less than 1.4dB and 3 - with the 20% operational bandwidth ranging from 2.7 to 3.3GHz, respectively.