RF ATE Systems Introduction

Though there are many RF applications, especially those with operating frequencies in the upper microwave and millimeter-wave spectrum, that rely on hand assembly and testing, there are now an increasing number of RF applications that require automated test equipment (ATE) and systems. For instance, the sheer volume and repetitiveness of semiconductor wafers and chips is much better suited for automated systems than hands-on testing for a variety of reasons. A few major factors are cost, time, and footprint of the test equipment and test station space required for personnel to perform hands on testing. Another key aspect is the repeatability of testing, which is much higher with ATE and automated testing systems than with hands-on testing.

Common RF Devices Testing With ATE
• Semiconductor wafers with high-speed digital or RF devices and components
• Wireless communications chips, such as those for cellular, WiFi, and other IoT applications
• High volume microwave monolithic integrated circuits (MMICs)
• Standard packaged RF devices/components
• Mid- or high-volume military or industry components that must meet quality control and qualifying performance
• Any device that can be automatically tested to EMC standards, such as FCC, CRISPR, CE, and etc.

There are also now many new ATE models that are designed with modular and programmable systems that can be used to perform RF, analog, power, digital control, high-speed digital signals, microwave, and millimeter-wave testing in a single unit, or using a single control unit and several modular accessories.

Types of ATE
• Bench-top or all-in-one units (often with GPIB or ethernet control)
• VXI-based card-type units (requires a computer control/interface and platform)
• Portable units that are PC-driven (often with ethernet or USB control)
• Programmable units that are standalone (often bench-top)
• Custom rack-mount units that may combine a variety of custom or purchased components possibly with custom interface and interconnect

Also, there are other types of ATE that are self-contained test units that are compact, portable, and can be synchronized and controlled by a common computer (PC-driven). Modular ATE tends to be lower cost and more customizable than purpose built ATE, but may also not be capable of the same level of speed and performance as purpose built ATE for a given application.

Common ATE Sub-components
• Signal sources (frequency synthesizers, local oscillators, PLLs, mixers, digital-to-analog converters etc.)
• Receivers (low noise amplifiers, analog-to-digital converters, mixers, isolators, filters, limiters, attenuators etc.)
• Splitters and combiners for splitting signal sources
• Interface sections which may be modular
• RF ports
• Digital control or high-speed digital test ports
• DC power ports
• Analog ports
• Upconverters/downconverters
• Direction couplers
• Power Amplifiers
• Voltage controlled oscillators
• Switch/Switch Matrices

The type of ATE system used depends on the application and its requirements. Some ATE systems are designed to complete a simple test that takes a relatively small amount of time with limited digital control, power, and RF port requirements. More complicated ATE testing could range to the latest 5G MIMO and beamforming testing that requires an anechoic chamber and complex test apparatus with a moving gimbal and possibly a multitude of probes.

RF ATE Requirement Categories
• Type of tests (single domain, multi-domain)
• Quantity and frequency of tests/RF ports
• RF input power levels and output power levels
• Digital control
• High-speed digital signals and RF testing
• Test throughput (dicates ATE test time, often limited by the handler dynamics)
• DC power supplies (type, power level, quantity)
• RF performance requirements (frequency, bandwidth, noise, phase noise, • VSWR, dynamic range. Linearity etc.)
• Test repeatability, calibration procedure/time, and zeroing procedure/time
• Configuration complexity and cost
• Size and cost of the ATE (relates to CAPEX and OPEX considerations)
• Maintenance and operating life of the ATE (relates to OPEX considerations)