Amphenol RF- Products

Amphenol RF introduces the AFI connector interface as a solution for board-to-board RF applications, especially for the military and broadband marketplace, by allowing maximum axial and radial misalignment while maintaining superior RF performance.

Amphenol RF developed the AFI connector interface as a solution for common electronics packaging and assembly constraints in modern systems. The AFI interface utilizes a proprietary configuration that allows for industry leading "float" to compensate for the axial and radial misalignment due to packaging tolerances. Float is a term commonly used to describe the movement that the interface can tolerate when mated. The AFI interface allows for a maximum radial misalignment of .030" (0.8 mm) and a maximum axial misalignment of .040" (1.0 mm).

The connector system consists of a plug connector with an individual floating bullet adapter pre-installed. The mating side of the system uses a corresponding jack connector consisting of an open port without bullet. In the mated system, the bullet acts like a flexible link and allows for misalignment due to package design

The interface is currently available in both 75 Ohm and 50 Ohm configurations. The 75 Ohm version is named AFI-75 and offers low loss performance from DC to 3 GHz. The 50 Ohm version, AFI-50, is designed for systems operating from DC to 6 GHz.

The AFI connector series is currently available in various configurations from surface mount to through-hole, in both straight and right angle. They are commonly utilized in interconnects between PC boards in various electronic packaging scenarios including mother-boards, daughter-boards and back-planes.

Amphenol RF's AFI solutions can be customized to satisfy specific packaging requirements. They can also be combined into multi-port gang-mate type configurations. Typical applications include from eight to twenty-four connections and can be staggered to reduce the size of the footprint.

Please contact Amphenol RF for more information or to discuss a custom solution.

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Amphenol RF expands its semi-rigid cable assembly capabilities

Semi-rigid cable assemblies are used to connect various system components throughout the military, telecom and datacom markets. Semi-rigid cable offers advantages such as increased shielding and improved electrical performance over flexible cable. These are critical issues in the engineering of these systems to ensure optimal signal and overall system integrity.

Over the years, Amphenol RF has provided semi-rigid assemblies as required to satisfy the request of certain customers. In order to provide the most complete solution for our entire customer base, Amphenol RF has expanded capabilities for production-level assembly. In this endeavor, we offer complete semi-rigid assembly lines in both our Nogales, Mexico and Shenzhen, China plants. With the use of modern automated cable cutters and strippers, temperature cycling ovens, and both manual and CNC bending equipment, Amphenol RF is now fully capable of manufacturing all types of semi-rigid cable assemblies. Whether it is delay lines for the power amplifier and filter markets or harness assemblies for the CMTS market, we can custom tailor a solution to your individual semi-rigid cable needs.

Amphenol RF offers a full range of connectors for the most common sizes of semi-rigid cable (.047, .086, .141, and .250 inches) as well as a significant portfolio of solutions for other cable sizes. Utilizing our worldwide design capability, we can customize assemblies to virtually any interface and configuration. As described elsewhere in this newsletter, we also have extensive electrical and mechanical testing capabilities, providing us with the ability to ensure conformance with even the most demanding customer specifications.

With our combination of high performance connectors and worldwide manufacturing and cable assembly capabilities, Amphenol RF is well positioned to be your complete global RF solutions provider. Please contact our Customer Support team to discuss your specific needs and count on us to provide the added value you require.

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Understanding the SMB

SMBs have a snap on interface and are usable frequency up to 4 GHz. Selecting the right Amphenol RF SMB for your application is sometimes difficult due to industry nomenclature and depth of product offering. SMB nomenclature is confusing because the center contact orientation is the reverse of most connectors, in that male center contacts go in SMB jacks, female center contacts go in SMB plugs. Within the SMB family of connectors, there are several different versions. These include Standard 50 Ohm, Mini-75, True 75 Ohm and High Density. Understanding the differences within the line will help you select the right connector for the application.

50 Ohm: 50 Ohm SMB is a subminiature snap on interface performing up to 4 GHz and available for a wide range of cable, PCB and receptacle configurations.

75 Ohm: Referred to as 75 Ohm, SMZ or BT43 and built into accordance to Mil standard 348, true 75 Ohm SMBs are larger than 50 Ohm SMBs. The interface is a true 75 Ohm interface that can be recognized by the dielectric surrounding the female contact on the cable plug. 75 Ohm connectors are available in our PosiLock design. True 75 Ohm SMB will not mate to a 50 Ohm connector.

Mini 75 Ohm: Minis, as they are often referred, are the same size as 50 Ohm SMBs. They have the same outer dimensions and the same contact sizes. The correct impedance is achieved by "cutting back" the Teflon insulator to the reference plain creating an air dielectric. Mini 75 Ohm SMBs can mate to a 50 Ohm SMB.

High Density: Roughly the same size as the 50 Ohm, High Density SMBs are a true 75 Ohm connector. With a smaller contact and Teflon insulator, High Density SMBs are easily identified by the Red insulator. To achieve 75 Ohms, the interface uses a smaller .015" diameter mating contact pin. Because of this High Density SMBs do not mate with the 50 Ohm version and should always be designed in as a mated pair.

SMBs can be used in a wide variety of applications, most notably component design, instrumentation and Test and Measurement. Understanding the system requirements, the overall requirements of the application and the basic make up of the SMB family will allow you to select the right connector for your situation.

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Amphenol RF provides the highest quality with its Network Analyzer upgrade

Amphenol RF, headquartered in Danbury, Connecticut, once again stays ahead of the competition with the purchase of the state-of-the-art Agilent E8361A PNA network analyzer. The E8361A covers a frequency range from 10 MHz up to 70 GHz. Performance specs are supplied up to 67 GHz. This new capability allows us to verify designs for high frequency connector series such as SMP, SSMP, 3.5 mm, 2.9 mm, 2.4 mm, and 1.85 mm.

Network Analyzer image will be here!

Additionally, the exceptionally wide bandwidth will enable very detailed TDR plots to be analyzed when designing new products or troubleshooting existing connector and cable assembly problems. TDR capability is a very powerful design and analysis tool. All of our engineers are trained in the theory and use of TDR and utilize it to help reduce the engineering design cycle.

From an instrument capability viewpoint, it has 94 dB of dynamic range at 67 GHz.
In addition, it has 32 measurement channels with up to 16,001 points per channel. Screen displays can be captured as either jpg or bmp files.

With its Windows 2000 operating system, firmware revisions can be downloaded and installed directly from the Agilent website.

We have purchased Calibration Kits for Type N, APC-7, APC-3.5, and APC-2.4. In addition, we also purchased a 1.85 mm E-Cal module that automatically calibrates the network analyzer for 1.85 mm without using mechanical calibration standards. Another advantage of the E-Cal module is that we can perform a one-time user characterization on any other series for which we have a cal kit. By using this method, The E-Cal module remembers the other Cal Kit standards and can quickly calibrate the network analyzer without the need to physically attach the mechanical standards. While the initial characterization is a bit time consuming (approximately 3 minutes), after that process is complete, you do not need to perform a manual calibration until the E-Cal unit is calibrated by Agilent. That is usually done once a year.

By interfacing the PNA with a computer, data can be uploaded into standard excel formats for further analysis.

This brand new, state of the art addition to our test lab ensures that we remain competitive in an increasingly competitive industry.

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Dave

Q: "How does one ensure high performance with minimal reflections and losses?"

A: It is important to understand that a connector is not just a mechanical connection between two transmission lines. It is also an RF connection with the express purpose of transferring as much of the RF energy as possible through the transmission line from Point A to Point B. All of the mechanical dimensions and materials used in the design of the connector will have an impact on its RF performance, particularly internal diameters. These diameters set up the transmission line impedances which must be close to the characteristic impedance (Zo) of the system (i.e. 50 ohms) or else the reflections in the connector will be excessive. Where significant deviations from Zo are required, perhaps for a barb or knurl on a contact, proper compensation steps must be added to minimize reflections.

When we design a connector, how can we be certain that it will perform well and with minimal reflections and losses? In order to ensure that we meet all RF performance requirements, Amphenol RF has been using a very powerful simulation tool called HFSS. This software package is manufactured by ANSOFT and we have been using it to design connectors since 1997. The tremendous advantage of the tool is that we can design the connector and simulate its performance without having to make actual samples and test them. We can try various modifications and have results within minutes or perhaps hours at the most for more complex designs. Only after we are satisfied with the results will we submit the design for samples to be made and then tested.

In this example, a BNC right angle plug for RG-58/U cable had a VSWR requirement of 1.25 maximum from DC- 4 GHz.

Mechanical Connector Drawing

The connector above was modeled in HFSS and is shown below. In HFSS, we need to make certain changes to the mechanical connector drawing. For this particular connector, these involve removing overlapping materials such as press fit insulators, adding the RG-58/U cable and setting up a proper BNC interface. Each component within the connector must be a separate identifiable entity and assigned a material property. This includes any air spaces. All external metal parts are unnecessary as HFSS defaults to a perfect conducting background. Since electric fields cannot penetrate metal surfaces, the metal body of the connector and external hardware are not needed for the simulation.

HFSS Model

After setting up the simulation in HFSS to run from DC-4 GHz, the initial VSWR results are shown below.

Initial Design VSWR Results

It can be seen that the VSWR meets the customer requirement up to 3 GHz, but from 3-4 GHz, it is above the spec and changes must be made to the design to improve the VSWR. In the next issue of Amphenol RF Connections, I'll describe how we use ANSOFT HFSS to help us modify the design and improve the VSWR performance. DW 9-12-03