Digitally controlled circulator and radio frequency identification reader having the same
AssigneeElectronics and Telecommunications Research Institute
InventorsSeok Bong Hyun, Kyung Hwan Park, Tae Young Kang, Seong Su Park
Life of this patent
Estimating the term…
Abstract
Provided are a digitally controlled circulator and a radio frequency identification (RFID) reader having the circulator. A power splitter is composed of lumped elements and the values of the elements are digitally changed using switching means, in which the transmission loss of a signal is controlled according to whether the reader is in a transmission state or a reception state. Therefore, the loss can be minimized, and the circulator can be miniaturized and priced down by an integrated circuit (IC) semiconductor process and mounted in a mobile terminal such as a cellular phone.
Claims11
A digitally controlled circulator comprising:
- first and second variable inductors connected between a first terminal and a second terminal in series;
- third and fourth variable inductors connected between the first terminal and a third terminal in series;
- a variable resistor connected between a first node and a second node, the first node being a junction of the first and second variable inductors and the second node being a junction of the third and fourth variable inductors;
- first, second, and third variable capacitors respectively connected between the first terminal and a ground terminal, between the first node and a ground terminal, and between the second node and a ground terminal;
- and
- a logic controller providing control values for changing each value of the first to fourth variable inductors, the variable resistor, and the first to third variable capacitors.
Dependencies are inferred from the claim text.