I really hope the Cybertruck is connected with the Starlink system. It would be sooo nice to go wherever you want to go with one and have a reliable signal.
The latency can "theoretically" be better than land based internet connections. Here is a cool video a guy did with all available information and a 3d rendering engine.
While the Ku and Ka bands are short enough to use such small antennas as you describe, the ability to get the signal from a general spot in the sky and help eliminate other signals, like coming from the tens to hundred of other Starlink satellites that would be in the sky, are probably why it has such a large antenna setup.
The wavelength doesn't really have much to do with it but it makes "matching" easier if the patches are half a wavelength or so.. The longest wavelength in the Starlink system will be 2.5 cm at the lower edge of Ku band with a half wavelength of 12.5 mm. Clearly manageable without any fancy matching networks (and their attendant losses).
Probably not. Focal length is immaterial except that the feed (or a subreflector) has to be placed there. And parabolic antennas are expensive to make and they have to be mechanically pointed. A pizza with the pepperoni bits being the patches in much simpler and cheaper to make and has the same aperture (approximately) as a dish of commensurate size and doesn't need a separate feed. Aparabolic antenna would have to track mechanically as would the simplest patch antenna but the patch antenna can be made into a phased array and the tracking done electronically.
Of course. See the video posted in No. 20.
The signals from the individual patches can be phased appropriately and summed to form beams with the width of the beam determined by the maxiumum distance between the pepperoni pieces. This is one of the big potential advantages on the CT as the patches can be placed meters apart and so the beams can be very narrow. The other advantage is that multiple beams can be formed simultaneously so as many sattelites as are visible can be tracked and hand off can be done instantaneously. Tesla has indicated that they are doing the trades on mechanical vs. phased array tracking on the home terminal antenna. We don't even know at this point if they are considering Starlink in their vehicles but if they are clearly mechanical tracking would be out of the question.
The antennas in the spacecraft are phased array for sure so yes, Tesla has familiarity with this technology. I started working on it in the 70's and I expect the state of the art has advanced dramatically in the intervening years. Your WiFi router, if it sports multiple antennas, contains adaptive beam forming capability. But this is not to say that there wouldn't be challenges in such a system.
If you want to form beams that are narrow in the vertical plane then you have to have vertical separation between the patches. I hadn't been thinking of that because I assumed that the vehicle would not connect to a SV less than, say, 30 ° above the horizon.
The narrower the beam, the more vertical separation. If this is an issue the solution would be to combine patches mounted in, for example, the lower windscreen with patches located in the roof glass.
The fact that the "noise temperature" of the sky is so much grater than Pensius's 2.9 K is really at the heart of this. Aperture for the sake of collecting flux from the desired satellite is no longer the totality of the problem. Collecting it from the direction of the desired emitter and not from undesired emitters is now a major consideration in communications systems design. Using beam forming from widely separated "antennas" clearly has lots of appeal. Whether it is feasible or not for a particular system will depend on many factors about which I have no information. It would be an interesting system to work on for sure.
"All I wanted was a chair that rotates....."
Yes, but they haven't been doing it well..... (/me eyes the derelict internet dish on his barn and makes a note to finally remove that damned P.O.C.)
