The GGB Industries, Inc., MODEL 50A probe sets new standards in microwave probing performance. Using low loss coaxial techniques, the Model 50A achieves an insertion loss of less than 1.0 db and a return loss of greater than 18 db through 50 GHz.

With its individually spring loaded, Beryllium-Copper or optional tungsten tips, the Model 50A provides reliable contacts, even when probing non-planar structures. This reliable low resistance contact is one of the keys to providing highly repeatable measurements. The Model 50A also provides direct viewing of the probe tips for accurate positioning.

The Model 50A can be mounted in various adaptors (see below) for use with standard microwave probe stations. Custom mounts are available as well.

Any pitch (tip spacing) from 25 to 1250 microns may be specified. The probe can be configured with Ground-Signal-Ground (G,S,G), Ground-Signal (G,S), or Signal-Ground (S,G) tip footprints.

Connection to the Model 50A is through a female 2.4mm connector which is also compatible with the V connector.


  • Durable
  • DC to 50 GHz
  • Any pitch from 25 to 1250 microns
  • Insertion loss less than 1.0 db
  • Return loss greater than 18 db
  • Measurement repeatability -80db
  • Individually spring loaded contacts
  • BeCu or Tungsten tips available
  • Variety of Footprints
  • Patented coaxial design
  • Available in thirteen styles
  • Custom configurations available

Click to enlarge image.

Close up of Model 67A Tips with 150 Micron Pitch almost touching a 50 ohm calibration load.

Typical Probe Card with Model 40 Probes.

Examples of the Multi-Contact Wedge which combines Multiple RF and DC Contacts.

Flexible Tips for Flexible Probing

EEach Model 50A has patented, independently spring loaded tips. Because the tips are flexible they minimize circuit damage, increase probe life, and most importantly, provide a reliable individually spring loaded contact for each point. With a small amount of overdrive, the point scrubs the surface to make a reliable contact free of dust, dirt, and oxide contamination. The ability to view the exact contact area eases probe positioning and allows for the precise positioning necessary for good LRM calibrations. The flexible tips even allow probing of non-planar surfaces such as ceramic substrates and laser diode structures.

Coaxial Transmission Improves Performance

The Model 50A uses a precision miniature 50 ohm coaxial cable from the probe tips to the connector interface. The coaxial design provides lower loss and less radiation than coplanar designs. The miniature coaxial cable is fabricated from flexible Beryllium-Copper which greatly improves the probe’s durability.

Probe Cards

The Model 50A as well as all of our RF probes can be mounted on standard 4.5 inch probe cards and/or custom-sized cards to provide a convenient method for testing wafers at high frequencies using standard automatic or manual probe stations. Picoprobe Probe Cards can incorporate our Model 50A probes for RF connections with DC needles for power and low frequency signals.

Multi-Contact Wedges

Our unique Multi-Contact Wedge designs accommodate multiple RF and DC contacts on a single, compact adapter. This compact design provides the user with a convenient method for testing wafers at high frequencies using standard automatic or manual probe stations. The user can choose from a variety of wiring options for the DC or power needles and select any combination of 40, 50, 67, and/or 110 GHz RF probes.

An Entire Line of Microwave Probes

Other models of RF probes are available with standard tip spacings of up to 2540 microns. Larger tip spacings are available as well. For special applications, the Model 40A can be mounted in custom adaptors, the coaxial line can be bent to fit tight spaces, and the tips can be configured to match extremely non-planar surfaces or non-symmetrically placed grounds.

Other options include:

  • Tungsten or Nickel probe tips;
  • high temperature and high power versions;
  • custom “chip” probes which have integrated series, parallel or termination components built into the signal tip.

For applications above 50 GHz, GGB Industries, Inc., offers a complete line of microwave probes operating up to 325 GHz (Model 325).

Several models are available with wave guide inputs: WR-22 for 33 to 50 GHz, WR-15 for 50 to 75 GHz, WR-12 for 60 to 90 GHz, WR-10 for 75 to 120 GHz, WR-8 for 90 to 140 GHz, WR-5 for 140 to 220 GHz, and WR-3 for 325 GHz.

The wave guide probes have an optional integral Bias T for active device measurements. Many other types and custom designs are available, so please call with your special application requirements.

Probing Expertise

With more than 25 years of probing experience, GGB Industries has broad capabilities in custom probe engineering and manufacturing. Our staff is accustomed to creating unique solutions for the most difficult probing requirements demanded by our customers. GGB Industries, Inc., is the leading supplier of high impedance active probes offering models with input capacitances of as low as .02 pF and frequency responses of up to 26.0 GHz.

Ordering Information

When ordering Model 50A probes, please use the following part numbering convention:

Model 50A – configuration – pitch – mounting style

Mounting Style:

Choose from thirteen adapter styles. Specify T, C, GR, P, DP, EDP, LP, Q, F, S, DS, VP, or RVP. Choose the appropriate mounting type for your application. The P, DP, EDP, LP, Q, S, DS, VP, and RVP styles have the connector pointing back at a 45 degree angle to give more working area above the probe. The DP, EDP, DS, VP, and RVP styles are used where extra clearance beneath the probe is needed. When using DP, EDP, and DS style probes, probe positioning is more difficult due to the increased probing angle since the probe points slide further forward for a given change in the Z axis than our other style probes. Custom mounting styles are available.


A 50A-GSG-150-P is a Model 50A with Ground, Signal, Ground configuration with 150 microns between each contact mounted in a P style adaptor.