Valid question.
I am not the person you asked the question of, but here is the answer;
Smart TVs have a built-in "WiFi-Chip" on the motherboard and its antenna hidden in the TV frame itself, exactly like the antennas in a Smartphone. The different radios on a Smart TV viz. OTA, WiFi, Bluetooth, Satellite, Zigbee etc. all operate at different frequency ranges and hence need their own antennas. Many of these antennas are either a) etched on the motherboard b) hidden within the plastic back frame or c) directly taped to it.
Axiom of RF Wireless - There can be no transmission/reception without an antenna either external or internal.
PS: Since RF Wireless is everywhere today and most people do not have much of an idea of this technology, i very highly recommend the book The Essential Guide to RF and Wireless by Carl Weisman for study. Expressly written for a non-technical audience, it explains everything simply and beautifully. It really gave me the invaluable overview and the grounding i needed to understand this important science/technology.