Wideband low-loss variable delay line and phase shifter
US6320480A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 1999 |
| Grant date | Nov 20, 2001 |
| Priority date | — |
| Expiry date | Oct 26, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01P1/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A programmable phase shifter (20, 40, 54, 60, 62) includes a variable delay line formed from a nonlinear transmission line (NLTL) (26, 28, 46, 28), which enables the device to be used in applications where the frequency of the input signal varies. A variable DC bias applied to the NLTL (26, 28, 46, 48) varies the NLTL's phase velocity and delay. Since the characteristic impedance of a transmission line changes as a function of the DC bias, the input voltage standing wave ratio (VSWR) also changes. In order to compensate for the change in the input VSWR, a pair of NLTLs (26, 28, 46, 48) are coupled at the input and output to a pair of hybrid couplers (22, 42). In an alternate embodiment of the invention, the hybrid couplers (22, 24) are replaced with 180.degree. power splitters (42, 44) in order to reduce distortion of the device. In other embodiments of the invention (40, 54), a nonlinear transmission lines are used to form both discretely variable and continuously variable digital phase shifters (60, 62).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.