Wireless Systems Design

RF Probe Makes High-Frequency Testing Easier

Wireless systems continue to migrate to higher and higher frequency bands. They hope to utilize uncrowned spectrums and larger data bandwidths. When it comes to testing, however, these increasingly high-frequency product components require very sophisticated test equipment. A typical setup, for example, consists of a vector network analyzer (VNA), wafer probe system, high-frequency probes, semi-rigid or flexible coaxial RF cables, and calibration substrates. The most critical part of the measurement system is perhaps the probe. It physically interfaces with the component that's being tested.

To make high-frequency wave probe contact as simple as measurements in the DC range, SUSS, Inc. has introduced the Z-Probe. This measurement probe enables a precise and safe contact with a planar-planar transition. The tip impedance is 50 Ω with a frequency range from DC to 40 GHz. Return loss in this frequency range is typically less than 20 dB. The probe's resistance is less than 0.006 Ω.

The company claims that its Z-Probes provide the highest number of touchdowns in the probe market today. A touchdown is defined as the motion of the probe tip as it comes in contact with the surface to be measured on a wafer, component, or printed-circuit board. Touchdown is a critical operation. The probe must exert enough force to measure the device under test (DUT), but not enough force to damage the DUT's surface. Here, the Z-Probes may have an advantage. The microwave transmission is totally isolated by air, which also helps to ensure a very low insertion loss of less than 0.8 dB from DC to −40 GHz.

In addition, the planar tip has precisely calculated separate contact springs. These springs move independently of one another. Using the latest microelectromechanical-systems (MEMS) technology, the tip allows perfect contact with the DUT with minimal overtravel and no DUT damage.

The Z-Probe may be used with the company's high-frequency probe system. That system includes positioners, substrates, and the SussCal calibration software. The Z-Probe also may be used with a variety of probe systems and positions from all major vendors.

Suss, Inc.
Suss Dr., Waterbury Center, VT 05677; (802) 244-5181, FAX: (802) 244-7853, www.suss.com.

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