Antenna device having multi-stage decoupling network circuit
An antenna device comprises: a first antenna; a second antenna; and a plurality of single decoupling network circuits DN_ 1 -DN_n which electromagnetically connect the first antenna and second antenna and remove a self-interference signal, wherein a multi-stage decoupling network circuit in which the DN_ 1 -DN_n are dependent-connected can be configured such that a Y 21 parameter of the multi-stage decoupling network circuit becomes equal to or lower than a predetermined value on frequencies f_ 1 -f_n, respectively.
1. A device comprising:
a transceiver including (i) a first antenna having a first antenna module, a first antenna port, and a first transmission line between the first antenna module and the first antenna port, (ii) a second antenna having a second antenna module, a second antenna port, and a second transmission line between the second antenna module and the second antenna port, and (iii) a plurality of decoupling network (DN) circuits; and
a processor configured to control the transceiver to transmit or receive wireless signals based on full duplex radio (FDR),
wherein, in at least one frequency, a ratio value between a voltage of the first antenna port and a specific current of the second antenna port is non-zero in at least one of the plurality of DN circuits,
wherein a real component of the ratio value is configured not to exceed a first threshold value based on a length of the first transmission line and a length of the second transmission line,
wherein the specific current of the second antenna port used for calculating the ratio value excludes a non-zero current of the second antenna module, and
wherein a sum of all ratio values of the plurality of DN circuits is zero for any frequency to cancel FDR-related self-interference between the first antenna and the second antenna.
2. The device of claim 1 , wherein each of the plurality of DN circuits includes:
a first node;
a second node connected to the first node through the first transmission line;
a third node; and
a fourth node connected to the third node through the second transmission line,
wherein the second node and the fourth node are connected through a third transmission line including a decoupling circuit.
3. The device of claim 2 , wherein the first node of a second DN circuit is connected to the second node of a first DN circuit, and
the third node of the second DN circuit is connected to the fourth node of the first DN circuit.
4. The device of claim 2 , wherein the decoupling circuit in the third transmission line is configured to make an imaginary component of the ratio value to be equal to or less than a second constant value.
5. The device of claim 2 , wherein the decoupling circuit is formed in a T-shaped structure.
6. The device of claim 2 , wherein the decoupling circuit includes a coupler.
7. The device of claim 2 , wherein each of the plurality of DN circuits includes:
a first shunt stub having one end connected to the second node and a remaining end grounded; and
a second shunt stub having one end connected to the fourth node and a remaining end grounded.
8. The device of claim 1 , wherein the plurality of DN circuits have different frequencies in which the ratio value becomes smaller than a threshold.
9. The device of claim 1 , wherein the plurality of DN circuits are cascaded with each other.
10. The device of claim 9 , wherein a multi-stage decoupling network circuit is configured based on the plurality of DN circuits.