SpaceX phase shifting array for receiving internet from satellites

SpaceX has a 2016 patent for a distributed Phase shifter array system for its internet satellites.

SpaceX is developing lighter and cheaper phased array antennas to receive internet from low-earth orbit satellites.

Low-Earth Orbit satellites will be will need to have fast tracking from receivers as they move quickly across the sky.

Receiving the internet with an affordable system is critical for the success of the low-earth orbiting satellites. Phased arrays are needed because mechanical systems would not be able to track the dozens of satellites that would needed to be tracked at any one spot. It would be like repointing at different cars passing on a highway.

Phased arrays are not mechanical so they would not need to physically move. The phased array receivers work but they are currently much to expensive. The costs are $20,000 to 40,000 now. The receiving systems need to get to below $1000 for a truly widespread rollout of low-earth orbiting internet satellites.

Most phased array antennas require a large number of phase shifter components for controlling the phase of the signal received-by or emitted-from individual antenna elements to control the angle of beamforming. With some embodiments of the present disclosure, an array of multiple phase shifters may be built on an integrated circuit (IC) chip (e.g., a semiconductor die). As a result, the cost, size, area, complexity, and power requirements of the phased array antenna system can be reduced. The present disclosure may be implementable, for example, as a two-dimensional (2-D) array of antennas for multi-beam receiving elements In some embodiments, the array of antennas can be one-dimensional. Since multiple phase shifters can be built on a single chip, the cost, size, and weight of the chip package can also be reduced. Furthermore, signal routing (e.g., trace routing), which includes distributing RF signals among phase shifters, can at least partially be implemented on the chip, as compared to the printed circuit board (PCB)-based signal routing of the conventional technology. In some embodiments, several chips each including multiple phase shifters can be combined into one phased array antenna system.

In some IC chip designs, parasitic capacitance may limit the frequency of transmitted signals because the cutoff frequency becomes too low, especially for gigahertz (GHz)-range signals. In some embodiments of the present disclosure, the parasitic capacitance can be absorbed by discrete inductors built on the IC chip or by inductance of the conductive traces of the IC. In some embodiments, the inputs and/or outputs of the IC chip can be terminated by optimal tunable resistors and/or balun transformers for better impedance matching (thereby transferring optimal power) and reduce noise from lower reflected RF waves.

In some embodiments, an apparatus includes a two-dimensional (2-D) array of phase shifters including a first plurality of the phase shifters and a second plurality of the phase shifters, wherein the first plurality of the phase shifters is arranged in a first direction of the 2-D array of phase shifters, and wherein the first plurality of the phase shifters is electrically coupled to a first radio frequency (RF) input. The second plurality of the phase shifters is arranged in a second direction of the 2-D array of phase shifters, and wherein the second plurality of the phase shifters is electrically coupled to a first radio frequency (RF) output. The first and second directions intersect each other.

In some embodiments, a method for phased array beamforming includes receiving a first radio frequency (RF) input signal; phase shifting the first RF input signal by a first plurality of phase shifters into a first plurality of phase-shifted RF signals; and receiving a second RF input signal. The method further includes phase shifting the second RF input signal by a second plurality of phase shifters into a second plurality of phase-shifted RF signals; combining a first phase-shifted RF signal from the first plurality of phase-shifted RF signals with a first phase-shifted RF signal from the second plurality of phase-shifted RF signals into a first RF output signal; and combining a second phase-shifted RF signal from the first plurality of phase-shifted RF signals with a second phase-shifted RF signal from the second plurality of phase-shifted RF signals into a second RF output signal.

It includes a two-dimensional (2-D) array of phase shifters including a first plurality of the phase shifters and a second plurality of the phase shifters. The first plurality of the phase shifters is arranged in a first direction of the 2-D array of phase shifters. The first plurality of the phase shifters is electrically connected to a first radio frequency (RF) input. The second plurality of the phase shifters is arranged in a second direction of the 2-D array of phase shifters. The second plurality of the phase shifters is electrically connected to a first radio frequency (RF) output. The first and second directions intersect each other.

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