Metamaterials vs. Phased Array Part 1
A new wave of flat panel antenna technology is emerging for satellite communications. These antennas have removed mechanical components, relying on software and electronics for steering making them available for mobile platforms like cars, boats, planes and more.
But not all flat panel antennas are the same. Kymeta’s metamaterials-based antenna is the first of its kind, and bears significant differences to other phased array flat panel antennas in the market today.
What it’s made of
Phased array antennas rely on microprocessor technology and software algorithms for combining signals received by numerous element antennas. In most cases, each antenna “panel” is populated with a collection of independent “patch” antennas and corresponding beam forming microchips. Think of it like one big antenna made up of multiple smaller antennas whose data must be processed and combined.
Kymeta’s antenna is built using a metamaterials toolset, which permits more elements and is a much more efficient way of creating a flat panel antenna. The metamaterial isn’t a specific thing. The metamaterial in mTennaTM technology is a metasurface and that metasurface is a glass structure.
Instead of reflecting microwaves (i.e., dish) or creating thousands of separate signals (i.e., phased array), Kymeta uses a thin structure with tunable “metamaterial” elements to create a holographic beam that can transmit and receive satellite signals.
The mTennaU7 ASM has 30,000 individual elements that act collectively as ‘pixels’ to create this holographic beam. By changing the pattern, the antenna can be pointed in different directions with no moving parts. Kymeta’s metamaterials foundation is also protected by nearly 200 international patents, so don’t expect to see another metamaterials-based flat panel antenna anytime soon.
How it works: power and performance
A phased array antenna requires “phase shifters” to adjust the phase and/or amplitude of each element antenna. In most phased array antennas, power amplifiers are combined with phase shifters to compensate for loss in active phase shifting, which leads to greater power consumption by the antenna.
The elements in a phased array are spaced farther apart, which means they need active electronic components to create the necessary phase and amplitude distribution to form a beam. The active electronic components draw more power and easily overheat, requiring a heating and cooling system that makes them thicker, more expensive and big power consumers (megawatts instead of watts).
Because of this, manufacturers must minimize the number of elements used, which leads to increased beam width in one or more dimensions and reduced scanning ability. Mechanical positioners are frequently used with phased arrays to spin panels into position, obtain full coverage with limited scanning and ensures the beam doesn’t interfere with other satellites.
Metamaterials enable Kymeta’s antenna to provide the dynamic, electronic beam-steering performance of a phased array, without the need for expensive and power-hungry phase shifters, related amplifiers and other components.
The antenna is “passive” because it doesn’t need active phase shifters, and the liquid crystal and glass used to manufacture it doesn’t have active RF. Without active phase shifters, it has more elements to create the right phase and amplitude distribution.
Kymeta’s antenna is capable of software-controlled/switchable polarization, which isn’t defined by the element polarization (as seen in phased array), but rather a software-generated radiation pattern. Kymeta’s software can easily turn elements off and on depending on the holographic equation.
The mTenna technology doesn’t have power amplifiers that create excess heat, and therefore doesn’t require a cooling system like traditional phased arrays. This means the antenna consumes only a few watts of power – as opposed to phased array antennas of equivalent size that typically consume more than a thousand watts.
The industry has defined most flat panel antennas as phased-array, but there are critical differences between a phased array and Kymeta’s metamaterials-based antenna that affect performance and a variety of other factors such as cost and scalability, which we’ll discuss in Part 2.