UWB balun with complete ground based on vertically mounted planar structure

Abstract

A novel UWB balun with complete ground based on vertically mounted planar structure is presented. Two mutually perpendicular planes comprise the proposed balun. The vertical configuration of double-sided parallel-strip line ensures complete ground in the horizontal plane and the cascading of seven-section quarter-wavelength transformers facilitates UWB functionality. For verification, a prototype balun is designed, fabricated and measured. The simulation and measurement agree well, exhibiting a bandwidth from 0 up to 8 GHz with good return loss, flat insertion losses and high stability of 180°p hase difference.

A compact wideband balun design using double‐sided parallel strip lines with over 9:1 bandwidth

“…Although the design has a tighter phase imbalance of ±4.5°, it only has 100 MHz bandwidth (at 0.96, 2.34 GHz) and occupies a larger area of approximately 80 mm × 52 mm, with 6.8 dB insertion loss. Reference 17 describes a UWB balun composed of seven cascaded quarter wavelength transformers in DSPSL on two perpendicular planes to provide better than 13 dB return loss from 0.86 to 8 GHz. Although the design has a UWB operation, it has a high phase and amplitude imbalance of ±12° and ±1 dB, respectively, but a limited application due to its non‐planar structure; however, it has a small size of approximately 30 mm × 22 mm × 35 mm.…”

Fully embedded ultra‐wideband multilayer balun into organic packaging substrate

“…Balun designs and configurations vary considerably. However, most of the reported baluns are either narrowband or with a fractional bandwidth (FBW) <100% [5][6][7], and only few UWB baluns with FBW >100% have been reported [8][9][10]; none of them are packaged. It is more challenging to design and realise packaged UBW balun with good performance, such as amplitude and phase balances over an ultra-wide operation frequency band.…”

Three‐dimensional high‐isolated dual‐band balun using double‐sided parallel‐strip line with inserted conductor plane

“…No wonder, due to the inherent out-of-phase frequency independence, double-sided parallel-strip line (DSPSL) [4][5][6][7] has attracted growing attention on investigating balun. Nevertheless, the DSPSL in the bottom layer [4] complicates the fabrication when suspended in metallic shields for high-power push-pull amplifiers.…”

“…Nevertheless, the DSPSL in the bottom layer [4] complicates the fabrication when suspended in metallic shields for high-power push-pull amplifiers. To tackle this thorny issue, another unique type of baluns based on vertically mounted planer (VMP) structures [5,6] is reported. However, the ideal matching and isolation between two outputs are not taken into consideration.…”

“…Although the usage of two external resistors in [7] may seem like a promising remedy for improving the dilemma, the unsatisfactory insertion losses make it only suitable for the narrow dual-band applications and the incomplete metal in bottom layer reappears. To the authors' knowledge, the study of the baluns with complete ground based on VMP [5,6] is still in infancy, not to mention the one also realised with isolation.…”