Low Loss Reflective Passive Phase Shifter using Time Delay Element
AssigneepSemi Corporation
InventorsJohn Birkbeck, Vikas Sharma, Kashish Pal
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Abstract
A phase shifter for altering the phase of a radio frequency signal is disclosed herein. A Lange coupler is used having reflective ports that are coupled to artificial transmission lines. The artificial transmission lines provide a reflection transmission path, the length of which can be determined by digital control lines. Transistors placed along the length of the central trace provide independent paths to ground that serve to shorten the electrical length of the ATL. Accordingly, by selectively turning the transistors on/off, the electrical length of the ATL can be selected and thus the amount of phase delay introduced by the phase shifter.
Claims13
A phase shifter comprising:
- (a) a radio frequency coupler having a input port, direct port, coupled port and isolation port;
- (b) a first central trace coupled between the direct port and ground;
- (c) a second central trace coupled between the coupled port and ground;
- (d) a first plurality of switches having a first terminal, a second terminal and a control terminal, the first terminal of each of the first plurality of switches coupled at intervals to the first central trace and the second terminal of each switch of the first plurality of switches coupled to ground;
- and
- (e) a second plurality of switches having a first terminal, a second terminal and a control terminal, the first terminal of each of the second plurality of switches coupled at intervals to the second central trace and the second terminal of each switch of the second plurality of switches coupled to ground.
Dependencies are inferred from the claim text.