Active Electronically Steered Array (AESA) technology has been used in military systems, mostly radars, for many years. AESA systems have traditionally been too expensive for most commercial applications, but new phased array technologies are quickly enabling low cost commercial applications such as vehicle sensors, satellite communications and 5G cellular systems. These systems use beamforming techniques to more precisely deliver RF energy in concentrated beams giving more bits per Hz in the targeted area while reducing interference.
New architectures, materials and devices are enabling this shift in the industry. In the satellite industry, Kymeta and Phasor are examples of companies that have re-configured phased array architectures for this commercial application. Phasor's innovation allows satellite signals to be extracted from very noisy background signals using a large number of digital and RF ASICs, each directly connected to a small patch antenna. These are assembled on a standard PCB board making them thin and conformable. The embedded microprocessors dynamically control the signal phases of each element to combine and steer the transmit and receive beams.
Kymeta has developed a unique metamaterial antenna technology that has tunable elements arranged in a precisely calculated pattern. RF energy is scattered when the elements are activated holographically generating a beam. The direction of the beam is defined by the specific elements that are electronically activated so it allows for both continuous and instantaneous changes in direction. The metamaterial technology uses this holographic approach to electronically acquire, steer, and lock a beam to any satellite so can rapidly and smoothly acquire and switch satellites even in a fast-moving LEO constellation without dropping the connection.
For 5G communication systems, new low cost commercial devices are hitting the market for mmWave applications from Anokiwave and Arralis. Anokiwave has released the world’s first Ka-band Transceiver Quad Core IC for 5G wireless networks. It operates at 27.5 to 30 GHz, supports 4 Tx/Rx radiating elements, includes all requisite beam steering controls for 5-bit phase/gain control, and operates in half duplex, enabling a single antenna to support both Tx and Rx operation. Additional unique features include gain compensation over temperature, temperature reporting all on a single chip. This type of device enables a compact chip and board AESA configuration with core chips driving sets of amplifier chips to boost the power for each Tx/Rx path. They will be releasing similar chips for other mmWave frequencies in the near future.
Arralis recently introduced fully integrated transmit and receive 94 GHz core chips. The devices make the highly desirable attenuation window of 94 GHz available for commercial applications such as fully autonomous radar for drones and self-driving vehicles as well as ‘wireless fiber’ communication speeds for 5G backhaul. The chips’ up-converter consists of a mixer with integrated medium power amplifier and offers conversion gain, high image rejection and an output power of more than 13 dBm. The down-converter consists of a low noise amplifier and a mixer giving a noise figure of less than 5 dB and a gain of more than 10 dB.
On the software and test side, many companies now offer very capable simulation and measurement systems that enable these designs to be designed and tested. Keysight’s suite of software tools now allow trade-offs in RF and digital beamforming performance to be easily modeled, using a connected suite of standard tools that streamlines the design process. NI AWR’s AWR’s Visual System Simulator allows end to end simulation of phased arrays including connection to LabVIEW so that simulated RF parts can be compared with LabVIEW algorithms and measurements. The modular architectures of PXI RF instruments lend themselves to the phase-coherent RF measurements required for MIMO and beamforming applications - NI and Keysight both have test systems for performing these types of measurements. Comsol’ new app server approach now offers a specific phased array simulation app and CST works with Antenna Magus to provide a full toolset for phased array simulation. ANSYS’ computational techniques in HFSS enhance the modeling capabilities required for analyzing finite phased antenna arrays as that is a major challenge to designers. So the tools are in place for further developments in this area.
These are just some examples of how the industry is shifting quickly to new phased array architectures using new materials and devices developed with more capable simulation and measurement tools. These new developments will enable lower cost, more capable systems for commercial applications as our industry shifts to from traditional radio architectures to AESA designs.