New switched‐network phase shifter with broadband characteristics

A Miniaturized 90° Schiffman Phase Shifter With Open-Circuited Trans-Directional Coupled Lines

“…Compared to the existing 90 • Schiffman phase shifter [4][5][6][7][8][13][14][15][16][17][18][19], the reference line of the proposed phase shifter is reduced by two thirds in length, an additional optimization variable added, and two transmission zeros near the operational frequency band achieved with the cost of the maximum realizable bandwidth of about 42%. The parametric analysis and detailed design procedure of the phase shifter are given.…”

“…When g is increased from 1.0 to 1.6, the phase bandwidth for 90 • ± 10 • is improved from 39.6% to 42.2%. Based on the analysis of Figures 4 and 6, the maximum realizable bandwidth of the proposed 90 • phase shifter is about 42%, which is less than that of the existing 90 • phase shifter [6][7][8][13][14][15][16][17][18][19]. However, the length of the reference line is reduced by two thirds, and practical applications require a moderate bandwidth such as the Global Position System (GPS operation at the frequency band of 1.164-1.587 GHz covering L1, L2 and L5 bands, the fractional bandwidth of 30.8%) and ultra-high frequency (UHF) Radio Frequency Identification (RFID at 840-960 MHz, 13.3%).…”

“…However, all the 90 • Schiffman phase shifters [4-8, 13, 14] and other 90 • differential phase shifters with broadside coupling structures [15], double microstrip-slot transitions [16], and TLs loaded open-or short-circuited stubs [17][18][19] require long reference lines (i.e., 3λ/4) which are difficult to miniaturize. In order to alleviate this problem, an open-circuited U-type coupled line was presented to replace the reference line [20].…”

Design of a Wideband Differential Phase Shifter With the Application of Genetic Algorithm

“…The switched-network phase shifter in [4], which is suitable for phase shift of less than 90 • , can offer a wideband and stable phase shift. The design details and exact performance of the 45 • phase shifter are not given.…”

“…This phase shifter is cited by [5] and exhibits an impedance bandwidth (|S 11 | < −10 dB) around 48% and a constant 45 • (±4 • ) phase difference over a frequency range of 24%. In this letter, Genetic Algorithm (GA) is applied to the optimization of the phase shifter proposed in [4] and a better performance of this type of phase shifter is obtained.…”