Based on the analysis in [30, 31], the structure can produce three resonant modes, and the center frequency and passband bandwidth are mainly determined by the electrical length [[theta].sub.0] of the QWR and the coupling gap, respectively.
The filter has three transmission zeros [T.sub.z1], [T.sub.z2] and [T.sub.z3] at the lower- and upper-stopbands, which are generated by the cross coupling between two open stubs and the coupling between the QWR and open stub .
The BPF for broadband channel is formed by three-coupled-line structure and two short stubs with different size loaded in 50 [ohm] feed lines, and the BPF for WLAN channel consists of two coupling QWRs and one open stub loaded in short parallel-coupling feed structure.
As shown in Figure 7(a), the BPF for WLAN application consists of two coupling QWRs, denoted by the length [l.sub.1] +[1.sub.2] + [l.sub.3] and width [w.sub.1], and short microstrip feedlines ([k.sub.1] + [k.sub.2], [w.sub.1]).
The QWR for optical thin films (OTF) can also be represented in terms of transmission line impedances for the power divider as
The impedances for the uncompensated power divider design were verified using the QWR for electrical impedances given by
The QWR can then be used to verify the impedance values for the multisegmented power divider as [Z.sub.1] = [(50 [ohms] [multiplied by] 35.35 [ohms]).sup.1/2] = 42.04 [ohms], where 50 [ohms] is matched to the artificially constructed impedance point 35.35 [ohms].
This expression is known as the QWR for optical thin films.
The use of the OAD and the QWR for OTFS can be seen as an extension from quarter-wave elements at optical frequencies to quarter-wave elements at microwave frequencies, and involves the MOT method.
Under previous RESPA provisions, a servicer had 20 days (excluding legal public holidays, Saturdays and Sundays) to acknowledge a QWR
. Dodd-Frank has shortened this to five days, with the QWR
response deadline cut from 6o days to 3o (although this may be extended another 15 days as long as the borrower is notified and provided a reason for the delay).