RADAR SYSTEMS: PERCEPTION SENSING
FOR ACTIVE SAFETY
ADI’s incomparable RF and microwave technologies create uncompromising radar systems performance
Radio detection and ranging (radar) systems leverage the transmission and reception of radio waves to determine the distance, velocity, and angle of objects in their field of view. Radar has a rich, 75-year history and is an integral technology spanning applications in aerospace and defense, to industrial automation, security, navigation, vital signs monitoring, and beyond.
Analog Devices, Inc. (ADI) continues to be at the forefront of the radar systems revolution by leveraging an unparalleled level of industry expertise, as well as market-leading RF and microwave capabilities to help drive radar system capability and designs. Our extensive portfolio of products—from amplifiers, mixers, PLLs, integrated transmitters and receivers, and VCOs to converters, power, and radar modules—helps engineers confidently and rapidly deploy the highest performance radar solutions for applications that demand the most challenging features.
Advantages of ADI 24 GHz Radar Technology
- Best-in-class transmit phase noise resulting in greater sensor effective range and accuracy
- Multichannel architecture allows beamforming for angle resolution
- High signal chain integration simplifies design and reduces time to market
- Full signal chain solution eases part selection and combination
- Separate 24 GHz transmit and receive paths to provide flexibility in radar front-end spatial design
TinyRad: 24 GHz Multichannel Radar System on a Small Form Factor PCB
This video shows Analog Devices 24 GHz multichannel radar solution. We will discuss various applications that this small form factor PCB development system targets, the Analog Devices components used, and the radar system parameters achievable.
TinyRad 24 GHz Demonstration Platform
The EV-TINYRAD24G is a credit card sized complete demonstration platform for 24 GHz radar system including antenna, RF and digital signal processing circuitry, and software GUI. The platform uses frequency modulated continuous wave (FMCW) radio signals and an integrated antenna array in a multiple input, multiple output (MIMO) radar architecture. The combined antennas, similar to digital beamforming (DBF), allow the TinyRad module to detect the distance, speed, and angular position of multiple targets simultaneously.
High Performance Integrated 24 GHz FMCW Radar Transceiver Chipset for Auto and Industrial Sensor Applications
The ADF5901 (24 GHz radar transmitter IC), ADF5904(24 GHz radar, 4-channel receiver IC), and the ADF4159 (FMCW Ramping PLL IC) form the basis of the RF chipset, which together enable the ADI 24 GHz radar solution. In this article, we describe in detail what are the performance characteristics of these ICs and how they can be combined to enable the high performance, 24 GHz radar solution, which can be used in applications from aerospace and defense, to industrial automation, security, navigation, vital signs monitoring, and automotive radar.
ADI’s Radar Technology in Markets and Applications
The vast majority of radar systems on the road today are based on 24 GHz discrete RF technology, including phase-locked loop, ramp generator, transmitter, receiver, and ADC. ADI continues to leverage its extensive automotive design expertise—and over 300 million automotive radar ICs shipped worldwide—to develop the next generation of ADAS and autonomous driving systems.
ADI radar technology delivers object detection, object tracking, localization, and mapping and is found in forklifts, locomotives, AGVs, construction vehicles, agriculture applications, and robotics—ensuring safety for people, objects, and other assets.
Aerospace and Defense
ADI's comprehensive portfolio and custom development provides complete RF-to-bits solutions for a wide range of commercial and defense radar systems.
Advanced ADI radar technology is being used in smart infrastructure for applications like adaptive traffic control systems (ATCS), which can automatically monitor traffic and adjust traffic control signals in real time. Radar is also incorporated in occupancy detection for inside/outside buildings to enhance energy savings, security, and worker productivity, while helping save lives, by virtue of its ability to “see” in all environments, including thick smoke, in darkness, and even through walls.
Highlighted Radar Solutions
Associated Radar Components
The ADF4159 consists of a low noise digital phase frequency detector (PFD), a precision charge pump, and a programmable reference divider. The Σ-Δ-based fractional interpolator allows programmable fractional-N division. The INT and FRAC registers define an overall N divider as N = INT + (FRAC/225).
The ADF4159 can be used to implement frequency shift keying (FSK) and phase shift keying (PSK) modulation. Frequency sweep modes are also available to generate various waveforms in the frequency domain, for example, sawtooth and triangular waveforms. Sweeps can be set to run automatically, or each step manually triggered by an external pulse. The ADF4159 features cycle slip reduction circuitry, which enables faster lock times without the need for modifications to the loop filter.
Control of all on-chip registers is via a simple 3-wire interface. The ADF4159 operates with an analog power supply in the range of 2.7 V to 3.45 V and a digital power supply in the range of 1.62 V to 1.98 V. The device can be powered down when not in use.
- Communications infrastructure
- Communications test equipment
- FMCW radars
The ADF4158 is a 6.1 GHz, fractional-N frequency synthesizer with modulation and waveform generation capability. It contains a 25-bit fixed modulus, allowing subhertz resolution at 6.1 GHz. It consists of a low noise digital phase frequency detector (PFD), a precision charge pump, and a programmable reference divider. There is a sigma-delta (Σ-Δ) based fractional interpolator to allow programmable fractional-N division. The INT and FRAC registers define an overall N-divider as N = INT + (FRAC/225).
The ADF4158 can be used to implement frequency shift keying (FSK) and phase shift keying (PSK) modulation. There are also a number of frequency sweep modes available, which generate various waveforms in the frequency domain, for example, sawtooth and triangular waveforms. Sweeps can be set to run automatically, or each step manually triggered by an external pulse. The ADF4158 features cycle slip reduction circuitry, which leads to faster lock times, without the need for modifications to the loop filter.
Control of all on-chip registers is via a simple 3-wire interface. The device operates with a power supply ranging from 2.7 V to 3.3 V and can be powered down when not in use.
- Frequency modulated continuous wave (FMCW) radar
- Communications test equipment
The AD7414/AD7415 are complete temperature monitoring systems in 6-lead and 5-lead SOT-23 packages. They contain a band gap temperature sensor and a 10-bit ADC to monitor and digitize the temperature reading to a resolution of 0.25°C.
The AD7414/AD7415 provide a 2-wire serial interface that is compatible with SMBus and I2C interfaces. The parts come in four versions: the AD7414/AD7415-0, AD7414/AD7415-1, AD7414-2, and AD7414-3. The AD7414/AD7415-0 and AD7414/AD7415-1 versions provide a choice of three different SMBus addresses for each version. All four AD7414 versions give the possibility of eight different I2C addresses while the two AD7415 versions allow up to six I2C addresses to be used.
The AD7414/AD7415’s 2.7 V supply voltage, low supply current, serial interface, and small package size make them ideal for a variety of applications, including personal computers, office equipment, cellular phones, and domestic appliances.
In the AD7414, on-chip registers can be programmed with high and low temperature limits, and an open-drain overtemperature indicator output (ALERT) becomes active when a programmed limit is exceeded. A configuration register allows programming of the state of the ALERT output (active high or active low). This output can be used as an interrupt or as an SMBus alert.
- Hard disk drives
- Personal computers
- Electronic test equipment
- Office equipment
- Domestic appliances
- Process control
- Cellular phones
The LT1963 series are low dropout regulators optimized for fast transient response. The devices are capable of supplying 1.5A of output current with a dropout voltage of 340mV. Operating quiescent current is 1mA, dropping to <1μA in shutdown. Quiescent current is well controlled; it does not rise in dropout as it does with many other regulators. In addition to fast transient response, the LT1963 regulators have very low output noise which makes them ideal for sensitive RF supply applications.
Output voltage range is from 1.21V to 20V. The LT1963 regulators are stable with output capacitors as low as 10µF. Internal protection circuitry includes reverse battery protection, current limiting, thermal limiting and reverse current protection. The devices are available in fixed output voltages of 1.5V, 1.8V, 2.5V, 3.3V and as an adjustable device with a 1.21V reference voltage. The LT1963 regulators are available in 5-lead TO-220, DD, 3-lead SOT-223, 8-lead SO, and Exposed Pad 16-lead TSSOP packages.
|LT1963A||Stable With Ceramic Output Capacitors|
- 3.3V to 2.5V Logic Power Supplies
- Post Regulator for Switching Supplies
The ADP5024 combines two high performance buck regulators and one low dropout (LDO) regulators in a small, 24-lead 4 mm × 4 mm LFCSP to meet demanding performance and board space requirements.
The high switching frequency of the buck regulators enables tiny multilayer external components and minimizes the board space. When the MODE pin is set high, the buck regulators operate in forced PWM mode. When the MODE pin is set low, the buck regulators operate in PWM mode when the load current is above a predefined threshold. When the load current falls below a pre-defined threshold, the regulator operates in power save mode (PSM), improving the light load efficiency.
The two bucks operate out of phase to reduce the input capacitor requirement. The low quiescent current, low dropout voltage, and wide input voltage range of the LDO extends the battery life of portable devices. The ADP5024 LDO maintains power supply rejection greater than 60 dB for frequencies as high as 10 kHz while operating with a low headroom voltage.
Regulators in the ADP5024 are activated though dedicated enable pins. The default output voltages can be either externally set in the adjustable version or factory programmable to a wide range of preset values in the fixed voltage version.
- Power for processors, ASICS, FPGAs, and RF chipsets
- Portable instrumentation and medical devices
- Space constrained devices
The AD8283 is designed for low cost, low power, compact size, flexibility, and ease of use. It contains six channels of a low noise preamplifier (LNA) with a programmable gain amplifier (PGA) and an antialiasing filter (AAF) plus one direct-to-ADC channel, all integrated with a single 12-bit analog-to-digital converter (ADC).
Each channel features a gain range of 16 dB to 34 dB in 6 dB increments and an ADC with a conversion rate of up to 80 MSPS. The combined input-referred noise voltage of the entire channel is 3.5 nV/√Hz at maximum gain. The channel is optimized for dynamic performance and low power in applications where a small package size is critical.
Fabricated in an advanced CMOS process, the AD8283 is available in a 10 mm × 10 mm, RoHS-compliant, 72-lead LFCSP. It is specified over the automotive temperature range of −40°C to +105°C.
- Automotive radar
Adaptive cruise control
Blind spot detection
The AD8285 is designed for low cost, low power, compact size, flexibility, and ease of use. It contains four channels of a low noise preamplifier (LNA) with a programmable gain amplifier (PGA) and an antialiasing filter (AAF) plus one direct-to-ADC channel, all integrated with a single 12-bit analog-to-digital converter (ADC).
Each channel features a gain range of 16 dB to 34 dB in 6 dB increments and an ADC with a conversion rate of up to 72 MSPS. The combined input referred noise voltage of the entire channel is 3.5 nV/√Hz at maximum gain. The channel is optimized for dynamic performance and low power in applications where a small package size is critical.
Fabricated in an advanced complementary metal oxide semiconductor (CMOS) process, the AD8285 is available in a 10 mm × 10 mm, RoHS compliant, 72-lead LFCSP that is specified over the automotive temperature range of −40°C to +105°C.
- Automotive radar
Adaptive cruise control
Blind spot detection
The ADA8282 is designed for applications that require low cost, low power, compact size, and flexibility. The ADA8282 has four parallel channels, each including a low noise preamplifier (LNA) and a programmable gain amplifier (PGA). The LNA and PGA combine to form a signal chain that features a gain range of 18 dB to 36 dB in 6 dB increments with a guaranteed minimum bandwidth of 5 MHz.
Using the highest power settings, the combined input referred voltage noise of the combined LNA and PGA channel is 3.4 nV/√Hz at maximum gain.
The ADA8282 can be configured in four power modes that trade off power and noise performance to optimize the performance according to the end application.
Fabricated in an advanced complementary metal-oxide semiconductor (CMOS) process, the ADA8282 is available in a 5 mm × 5 mm, RoHS-compliant, 32-lead LFCSP. It is specified over the automotive temperature range of −40°C to +125°C.
- Automotive radar
Adaptive cruise control
Blind spot detection
The ADAR7251 is a 16-bit, 4-channel, simultaneous sampling analog-to-digital converter (ADC) designed especially for applications such as automotive LSR-FMCW or FSK-FMCW radar systems. Each of the four channels contains a low noise amplifier (LNA), a programmable gain amplifier (PGA), an equalizer, a multibit Σ-Δ ADC, and a decimation filter.
The front-end circuitry is designed to allow direct connection to an MMIC output with few external passive components. The ADAR7251 eliminates the need for a high order antialiasing filter, driver op amps, and external bipolar supplies. The ADAR7251 also offers precise channel-to-channel drift matching.
The ADAR7251 features an on-chip phase-locked loop (PLL) that allows a range of clock frequencies for flexibility in the system. The CONV_START input and DATA_READY output signals synchronize the ADC with an external ramp for applications such as FSK-FMCW radar.
The ADAR7251 supports serial and parallel interfaces at programmable sample rates from 300 kSPS to 1.8 MSPS, as well as easy connections to digital signal processors (DSPs) and microcontroller units (MCUs) in the system.
- Automotive LSR systems
- Data acquisition systems
The processor offers performance up to 400 MHz, as well as lowest power consumption at <100mW. Produced with a low-power and low-voltage design methodology, they provide world-class power management and performance.
By integrating a rich set of industry-leading system peripherals, large on-chip memory & a high speed external memory interface, this Blackfin processor is the platform of choice for next-generation applications that require RISC-like programmability, multimedia support, and leading-edge signal processing in one integrated package. These applications span a wide array of markets, from automotive systems to embedded industrial, instrumentation, video/image analysis, biometric and control applications.
Radar Evaluation Boards
The EV-TINYRAD24G is a radar evaluation module that allows the implementation and testing of radar sensing applications in the 24 GHz industrial, scientific, and medical (ISM) band. The EV-TINYRAD24G uses frequency modulated continuous wave (FMCW) radio signals and an integrated antenna array in a multiple input multiple output (MIMO) radar scheme. The combined antennas, similar to digital beamforming (DBF), allow the TINYRAD module to detect the distance, speed, and angular position of multiple targets simultaneously. The raw analog-to-digital converter (ADC) data is forwarded by the onboard Blackfin® ADSP-BF706 digital signal processor (DSP) to the PC. The PC evaluation software, with an included graphical user interface (GUI), performs radar signal processing steps to yield radar point clouds that can be visualized as range doppler or range angle plots. The radar algorithms are also available as MATLAB™ and Python™ code and enable quick development of user defined, application specific code.
The EV-RADAR-MMIC2 evaluation board is designed to evaluate the performance of the ADF5901, a 24 GHz transmitter (Tx) monolithic microwave integrated circuit (MMIC); the ADF5904, a 24 GHz receiver (Rx) MMIC; and the ADF4159, a 13 GHz phase-locked loop (PLL) for a frequency modulated continuous wave (FMCW) radar system.
The EV-ADAR-D2S adapter board contains the eight AD8129 differential receiver amplifiers that convert the baseband ADF5904 differential signals to single-ended signals with a 20 dB gain.
The evaluation kit also contains the Analog Devices EV-RADAR-MMIC Software, which is compatible with Windows® XP and later Windows versions to allow easy programming of the device.
The EV-RADAR-MMIC2 evaluation board requires an SDP-S or SDP-B board (not supplied with the kit). The SDP board allows software programming of all the devices.
Full specifications for the ADF5901, ADF5904, and ADF4159 are listed in the ADF5901 data sheet, the ADF5904 data sheet, and the ADF4159 data sheet available from Analog Devices and should be consulted in conjunction with UG-866 when using the evaluation board.
Interactive Signal Chains
Radar Basics: How to Build a 24 GHz FMCW Radar System
Rarely Asked Questions
How to Optimize Switching Power Supply Layout by Minimizing Hot Loop PCB ESRs and ESLs
Rarely Asked Questions
How to Achieve Ultrafast Power Supply Transient Response for RF Applications
- Combining the Best of Both Worlds: True Time Delays and Phase Shifters
High IF Sampling Puts Wideband Software-Defined Radio Within Reach
Radar, the Car’s Virtual Eye
The Autonomous Industrial Revolution
- MAX25240/39: HV Low Iq 6A/4A Buck-Boost Converter 400kHz/2.1MHz
- High Power Switches in SOI: ADRF5144 and ADRF5141
- Unboxing the EVAL-ADAQ8088EBZ and Setup Using a Network Analyzer
- ADI X-Band Developer's Kit
- Unboxing & Setting Up the MxFE® Evaluation Board