US 12,148,977 B2
Directional coupler having wide band high directivity and flat frequency response
Daniel Hoshiko, University Heights, OH (US)
Assigned to BIRD TECHNOLOGIES GROUP INC., Solon, OH (US)
Appl. No. 18/698,569
Filed by BIRD TECHNOLOGIES GROUP INC., Solon, OH (US)
PCT Filed Jun. 15, 2023, PCT No. PCT/US2023/025478
§ 371(c)(1), (2) Date Apr. 4, 2024,
PCT Pub. No. WO2023/244761, PCT Pub. Date Dec. 21, 2023.
Claims priority of provisional application 63/352,228, filed on Jun. 15, 2022.
Claims priority of provisional application 63/393,236, filed on Jul. 29, 2022.
Prior Publication US 2024/0332777 A1, Oct. 3, 2024
Int. Cl. H03F 1/02 (2006.01); H01P 5/18 (2006.01); H03F 3/45 (2006.01)
CPC H01P 5/18 (2013.01) [H03F 3/45475 (2013.01); H03F 2200/451 (2013.01)] 30 Claims
OG exemplary drawing
 
1. A directional coupler circuit comprising:
a capacitive divider for sampling a voltage on a center conductor of a transmission line;
a coil having mutual inductance with the center conductor for sampling current travelling in a forward direction and a reflected direction on the transmission line, the coil having an upstream end and a downstream end, wherein the coil is configured for sampling current travelling in both the forward direction and the reflected direction on the transmission line;
a combined forward path comprising a forward transimpedance operational amplifier, a voltage operational amplifier, and a forward RF power output;
the voltage operational amplifier receives a sample of the voltage on the transmission line from the capacitive divider and outputs a voltage representative of the voltage on the transmission line; the sample of voltage on the transmission line containing both the forward and reflected voltage on the transmission line, with the forward and reflected voltage being in-phase with each other;
the forward transimpedance operational amplifier receives an upstream sample of a current travelling on the transmission line from the upstream end of the coil, the upstream sample of current comprising both a current sample travelling in the forward direction and a current sample travelling in the reflected direction on the transmission line; the current sample travelling in the forward direction is in phase with the forward voltage on the transmission line, and the current sample travelling in the reflected direction is equal in magnitude with and 180 degrees out of phase from the sample of the reflected voltage on the transmission line; the forward transimpedance operational amplifier outputs a voltage representative of the upstream sample of current travelling on the transmission line; and
wherein the outputs of the forward transimpedance operational amplifier and the voltage operational amplifier are combined and outputted using the forward RF power output; when combined, the voltage representation of the current sample travelling in the reflected direction cancels with the sample of the reflected voltage on the transmission line, thereby only a voltage representative of RF power travelling in the forward direction on the transmission line is present at the forward RF power output;
a combined reflected path comprising a reflected transimpedance operational amplifier, a voltage operational amplifier, and a reflected RF power output;
the voltage operational amplifier receives a sample of the voltage on the transmission line from the capacitive divider and outputs a voltage representative of the voltage on the transmission line; the sample of voltage on the transmission line containing both the forward and reflected voltage on the transmission line, with the forward and reflected voltage being in-phase with each other;
the reflected transimpedance operational amplifier receives a downstream sample of a current travelling on the transmission line from the downstream end of the coil; the downstream sample of current comprising both a current sample travelling in the reflected direction and a current sample travelling in the forward direction on the transmission line; the current sample travelling in the reflected direction is in phase with the reflected voltage on the transmission line and the current sample travelling in the forward direction is equal in magnitude with and 180 degrees out of phase from the sample of forward voltage on the transmission line; reflected transimpedance operational amplifier outputs a voltage representative of the downstream current travelling on the transmission line; and
wherein the outputs of the reflected transimpedance operational amplifier and the voltage operational amplifier are combined and outputted using the reflected RF power output; when combined, the voltage representation of the current sample travelling in the forward direction cancels with the sample of the forward voltage on the transmission line, thereby only a voltage representative of RF power travelling in the reflected direction on the transmission line is present at the reflected RF power output.