At a more leisurely pace
All active phased array technologies are based on the same fundamental physics. However, solutions can be based on a range of architectures.
The differences centre on how and where the signals at each array element are combined or divided.
Traditional phased arrays combine at RF (radio frequency) which requires expensive, bulky components to maintain performance. They do not scale easily to larger aperture sizes due to significant transmission losses. Complexity increases as multiple beams are implemented and additional local oscillators may be required to mitigate transmission losses by combining at intermediate frequency.
Digitising the signal at, or near, each element does allow significant control and hundreds of beams. However, very complex, high-speed digital processors and power-hungry DACs and ADCs are required across the aperture making scaling up demanding, particularly on the receive antenna, and dissipating high heat across the system.
The way we do it
Hanwha Phasor’s technology demonstrator deploys an inventive and patented approach to implementing our phased array antenna: analogue IQ baseband combining across the antenna enabled by an application-specific integrated circuit (ASIC). This enables an active phased array terminal capable of GEO, HEO, MEO and LEO connectivity, while delivering a superior experience for users. The array consumes less power than pure digital alternatives, generates very high performance for the platform real estate occupied and offers an elegant solution to this intrinsic system trade-off.
At each radiating element, the signal is mixed up or down from RF to analogue IQ baseband. This allows the rest of the system functions (phase-shifters, attenuators, polarisation control and combining and distributing across the array) to be carried out at the lowest frequency possible. These low frequency circuits are less complex to design, more stable, more efficient and less ‘lossy’ than those of other AESA architectures.
All this capability is packaged within ultra-slim core modules of just 25mm (1 inch) deep (with the fully integrated antenna amounting to no more than seven centimetres/2 ¾ inches), offering multiple mission-critical and operational advantages:
Since the M6 was conceived, bandwidth requirements have increased dramatically. The M6 has now become a vehicle for developing features and resilience and systems integration, learning from which will be carried over to our build-standard aero product with new architecture for superior bandwidth.
Each ASIC is closely coupled to four resonant patch antennas operating at the required frequencies (10.7 – 12.75 GHz for receive and 14.0 – 14.5 GHz for transmit).
Some 153 (transmit) and 112 (receive) ASICs are connected to 612 and 448 patch antennas respectively in the 180 x 360 mm core module – in aggregate, some 3,672 antenna elements on the transmit aperture and 2,688 on the receive of our M6 (six-module) antenna system.
Embedded in the core module, these integrated circuits dynamically control the signal phasing of each element patch antenna in real time, steering the transmit and receive beams in any direction. This will enable the array to rapidly acquire and track any satellite in any orbit from a moving platform, even in extreme conditions.
The RF signal received by the patch antennas is down-converted to give a baseband IQ output. Each output from an individual ASIC is constructively combined with the output of every other element in the system to produce the global baseband output. This combining method incorporates a proprietary algorithm to maximise the signal strength from the direction of the satellite.
Conversely, the baseband IQ signal is fed to each of the transmit ASICs for up-conversion to the required Ku band transmit frequency and points the beam toward the satellite.
M6 technology demonstrator
Integrated antenna control unit – single LRU solution
Standard L-band modem interface (analog baseband optional), Web GUI and OpenAMIP over Ethernet antenna controls. Interoperable with most modems and no proprietary interface required
Solid-state antenna – no moving parts, nothing to wear out, no drive bearings issues
Built-in dual GNSS receivers and INS removes need for external navigation (PNT) input
Each ASIC is connected to four patch antennas, reducing power consumption and external noise injection
Each identical module is a tightly integrated stack of PCBAs, providing structural support and thermal management in a very condensed package
Optimised element spacing for high gain and top scanning performance
Each antenna element can be independently controlled for both phase and amplitude, enabling highly advanced beamforming
Up/down conversion between RF analog and baseband takes place in our proprietary ASICs, delivering a power consumption dividend versus pure digital conversion
Fully sealed and protected for all-weather operation – no user maintenance required
The PCBA sandwich
Each identical core module is a tightly integrated stack of printed circuit boards (PCBAs). This provides structural support and thermal management in a very condensed array that can be conformed and shaped to most curved surfaces, minimising drag, weight and visual impact.
The top board hosts the array of element patch antennas and Hanwha Phasor’s patented ASIC microchips on the underside.
A second PCBA provides the control and communications. Additional boards provide power and distribute the sensitive local oscillator signals.
Multiple transmit and receive modules are used to create the desired aperture size. Today, we are prototyping a fully integrated six-module aperture system. Tomorrow, we are aiming to flex our antenna’s intrinsic modularity with an extended range of standard apertures designed to meet link requirements precisely.