A Novel Ultra-Wideband Differential Filter Based on Double-Sided Parallel-Strip Line

Wideband Balanced Filters With Wideband Common Mode Suppression Using Coupled Lines

“…In the past few years, many microstrip balanced filters for single-band, dual-band and wideband with common mode suppression have been realized [3][4][5][6][7][8][9][10][11][12][13][14][15]. In [5,6], branch-line couplers are cascaded to realize a wide passband for the differential mode; however, out-of-band common mode suppression cannot be solved.…”

“…Broadside coupled microstrip-slotmicrostrip structures can also be utilized to realize an ultra-wideband (UWB) differential filter in [7][8][9][10], but the transmission zeros near the differential mode passband are difficult to increase. Some ultra-wideband (UWB) balanced bandpass filters based on double-sided parallel-strip lines (DSPSLs) are introduced in [11,12], but the upper stopband for the differential mode should be further extended. Several wideband balanced filters with high selectivity for the differential mode passband are introduced in our former works [13,14], but the common mode suppression level is not so good.…”

“…Therefore, when the coupled circuits of Fig. 1 are used to design balanced filters, the symmetrical shorted stubs can be used to design a high selectivity passband for the differential mode, and the asymmetrical open/shorted stubs can be used to suppress common mode over a wide band, and the asymmetrical circuit model can have more freedom to design different balanced circuits, which are different from former balanced circuits in [3][4][5][6][7][8][9][10][11][12][13][14][15]. Moreover, some other stubs can also be considered to increase the passband order and transmission zeros for the differential mode [16], and the increased transmission zeros can be used to further improve the common mode suppression.…”

Compact Balanced Uwb BPF Based on Hmsiw and D-DGS

“…In practical circuits, common-mode noise still interferes with differential signal path, which will degrade the signal integrity of a high speed circuit system [1][2][3][4][5][6][7][8]. The balanced bandpass filters (BPFs) are effective in removing the common-mode noises but still keep good signal integrity performance for the differential signals in their passbands [9][10][11][12][13][14][15][16].…”

“…Some balanced filters based on branch-line structures were presented in [9,14,15], which obtained good common-mode suppression in the passband and high selectivity for the differential mode but relatively high insertion loss. In addition, differential filters were constructed in [10,11] by taking advantage of the parallel-coupled lines which had some limitations for the special structures. Some balanced filters [12,13] aim at UWB applications, but their sizes are relatively large.…”