Broadband Branch Line Balun using Meander line on Silicon Substrate

A Compact and Broadband Balun Design for Lte Applications

“…A simple and easy way to manufacture a wideband balun using a coplanar waveguide (CPW) structure was studied in [22]. A branch line balun having meandered branches and printed on a high resistive silicon substrate to achieve tight coupling was proposed in [23]. Table 1 summarizes the performances of all the aforementioned wideband baluns [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] in terms of operating frequency band, impedance bandwidth, size (where λ o is the lowest operating frequency), S 21 /S 31 values, employed technologies/techniques and complexity.…”

“…A branch line balun having meandered branches and printed on a high resistive silicon substrate to achieve tight coupling was proposed in [23]. Table 1 summarizes the performances of all the aforementioned wideband baluns [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] in terms of operating frequency band, impedance bandwidth, size (where λ o is the lowest operating frequency), S 21 /S 31 values, employed technologies/techniques and complexity. By examining all the aforementioned wideband baluns, it was found that the proposed balun has the advantage of accomplishing a broader frequency range than published works [6][7][8][9][10][11][12][14][15][16][17][18][19][20][21][22][23].…”

“…In contrast to [11,16,[19][20][21]23], this article proposes a printed wideband balun that accomplishes both a size reduction and the potential to simultaneously cover the whole frequency band of LTE from 700 MHz to 2600 MHz. In terms of complexity, it can be noted that the proposed balun has come up with less complexity than the works in [8,[10][11][12][13][14]15].…”

“…In terms of complexity, it can be noted that the proposed balun has come up with less complexity than the works in [8,[10][11][12][13][14]15]. Moreover, this proposed balun was printed on a low permittivity substrate compared to works in [11,23], which makes the proposed balun a good candidate to be printed exactly underneath the ground plane of the authors' balanced antenna in [24] which in turn may not affect the whole system performance. Thus, this balun is proposed to be used in the measurements of any balanced feed microwave structure, since it has a wide impedance bandwidth and easy to be integrated within the layout of the ground/handset surface.…”