US 12,341,729 B2
Time-division duplex (TDD) antenna system
Donald L. Runyon, Duluth, GA (US); Charles M. Luke, Cumming, GA (US); Alex C. Panos, Cumming, GA (US); and Kurt A. Zimmerman, Dunwoody, GA (US)
Assigned to ViaSat, Inc.
Appl. No. 17/278,531
Filed by ViaSat, Inc., Carlsbad, CA (US)
PCT Filed Oct. 3, 2019, PCT No. PCT/US2019/054555
§ 371(c)(1), (2) Date Mar. 22, 2021,
PCT Pub. No. WO2020/072811, PCT Pub. Date Apr. 9, 2020.
Claims priority of provisional application 62/768,026, filed on Nov. 15, 2018.
Claims priority of provisional application 62/741,311, filed on Oct. 4, 2018.
Prior Publication US 2022/0038251 A1, Feb. 3, 2022
Int. Cl. H04L 5/14 (2006.01); H04B 17/318 (2015.01); H04W 24/08 (2009.01)
CPC H04L 5/14 (2013.01) [H04B 17/318 (2015.01); H04W 24/08 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A self-synchronizing time-division duplex (TDD) antenna system comprising:
an antenna configured to communicate a transmit signal and a receive signal;
a calibration circuit; and
an antenna circuit coupled to the antenna and to a user communication system via at least one transmission line cable, the antenna circuit comprising:
a transmission line measurement circuit configured to generate a calibration signal and to determine signal loss between the user communication system and the antenna circuit through the at least one transmission line cable based on a return signal compared to the calibration signal;
an amplitude adjustment circuit configured to adjust amplitude of at least one of the transmit and receive signals based on the determined signal loss;
a transmit detection circuit configured to monitor signal power of the transmit signal obtained from the user communication system via the at least one transmission line cable; and
a controller configured to switch the amplitude adjustment circuit from a receive mode to a transmit mode in response to the monitored signal power exceeding a predetermined threshold, wherein in the receive mode the amplitude adjustment circuit applies a receive amplitude adjustment along a signal path to the receive signal, and in the transmit mode the amplitude adjustment circuit applies a transmit amplitude adjustment along the signal path to the transmit signal;
wherein the calibration circuit comprises:
a first switch in communication with a first transmission line cable of the at least one transmission line cable;
a second switch in communication with a second transmission line cable of the at least one transmission line cable;
wherein during a normal operation mode, the first switch connects the first transmission line cable to the signal path to facilitate propagation of the transmit and receive signals between the user communication system and the antenna via the first and second transmission line cable,
wherein during a calibration mode, the first and second switches are switched to be disconnected from the signal path and to provide the calibration signal to the first transmission line cable which is retransmitted back to the antenna circuit as the return signal along the second transmission line cable to determine the signal loss of the first and second transmission line cables, and
an extraction circuit for receiving DC power from the user communication system via at least one of the first and second transmission line cables and providing the DC power to the antenna circuit.