The Performance Leader in Microwave Connectors SSBP High Performance Blind-Mate Millimeter Wave Coax Contacts in Standard Multi-Contact Connectors Southwest Microwave, Inc. www.southwestmicrowave.com

Southwest Microwave, Inc. SSBP High Performance Blind-Mate Millimeter Wave Coax Contacts in Standard Multi-Contact Connectors Bucky Clyatt, SSB Product Development Manager Southwest Microwave, Inc., Tempe, Arizona Author’s Biography Bucky Clyatt received his BSME education at Arizona State University specializing in mechanical design and kinematics. He is the SSB* Product Development Manager at Southwest Microwave, Inc., Microwave Products Division, responsible for engineering and development of all SSB* connector products. He joined the company in 2003 as Engineering Manager and functioned in...

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Blind Mate Coax Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Motivation for New Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 SSBP Coax Design Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 SSBP Coax Design Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Test Methods...

Introduction Engineers designing systems with multiple, high performance microwave and millimeter wave blind-mate coax connectors functioning as contacts in standard circular or rectangular host connector housings are no longer limited to host connectors with layouts accommodating only the large Size 8 or Size 12 contacts, or to special/custom connectors. Southwest Microwave, Inc. (SMI) has developed millimeter wave coax contacts with the same millimeter wave electrical connector performance from DC to greater than 65 GHz as standard Super SMA, 2.92mm, 2.40mm and 1.85mm millimeter wave connectors....

Motivation for New Development Based upon review of the performance and sizes of the blind-mate coaxes presently available, it was apparent to SMI that applications would exist for higher density, higher frequency, lower loss blind mate coax contacts in sizes proportional to the latest high performance coax flex cables with outer conductor diameters from .047 to .265 for use in standard multi-contact host connectors. Market studies indicated that they must be completely interchangeable with equivalent standard, miniature signal contact sizes defined in MIL-C-39029. These are the most common miniature...

Southwest Microwave has designated them as SSBP. They are now available in Sizes 20, 16, and 8 for MIL-DTL-38999 Series I, III, and IV connectors and Size 20HD for MIL-DTL-24308 connectors. Because of their envelope commonalities with contact envelopes per MIL-C-39029, the SSBP coaxes are adaptable to many standard host connectors for future design consideration. Our present focus is on MIL-DTL-38999, MIL-DTL-24308 and one special host connector application to be mentioned later in this paper. Figure 3: Detail view of the 38999 connector and SSBP coax installation sequence . SSBP Coax Design...

Figure 4: Mixed Size 20 and Size 16 SSBP coaxes and signal contacts installed in a MIL-DTL-38999 Series III connector pair . Southwest Microwave, Inc. • Tempe, Arizona 85284 USA • 480-783-0201 • www.southwestmicrowave.com

SSBP Coax features The SSBP pin coax outer contact mating end is a solid, heat treated beryllium copper tube with a nose radiused edge. All beryllium copper (BeCu) parts are plated gold over nickel per MIL-G-45204 and MIL-C-26074. There are no exposed spring fingers or slots that could be damaged or contribute to EMI emission. In standard host connectors, the alignment of SSBP coaxes is triple redundant. As the host connectors are initially mated, each pin coax outer contact tube encounters the closed entry socket contact insulator chamfer, the SSBP socket coax alignment sleeve entry chamfer,...

A better blind-mate coax test method suggested by William Oldfield1 is Frequency Gating by Time Domain (FGT). This allows gating of the time domain location of interest and displaying the return loss of this portion as return loss versus frequency. Data using each of the above two methods for evaluating insertion loss and return loss or VSWR is displayed in Tables 1 & 2. SSBP Test Data* S11 Base Cable ASSY S11 Cable with SSBP Table 1: Comparison of base cable assembly to cable assembly with Size 16 SSBP. Test Measurement Reference All data was measured using an ANRITSU VNA 37297D with 1.85 mm...

System impedances other than 50Ω can also be provided using SSBP coaxes. 50Ω Sizes 20, 20HD, and 16 are already available as previously noted. We have verified the feasibility of 75Ω in Size 16 and Size 12 SSBP and 95Ω in Size 12 SSBP. All SSBP coax Sizes, regardless of impedance value, use the same outer contacts and hardware as the corresponding 50Ω SSBP coax sizes. Therefore, respective size envelopes remain unchanged. SSBP EMI Features The configurations of the interfaces in all sizes of SSBP coaxes provide a high level of EMI isolation. The only openings in the outer conductor of a mated...

SSBP Cable Applications A variety of solid PTFE dielectric and low density dielectric, low loss cables have been used thus far with SSBP coaxes. These are listed in Table 4 along with some of the respective cable properties. Maximum cable size for any SSBP coax size is limited by the maximum allowable O.D. of the SSBP pin or socket coax cable bushing which corresponds to the contact crimp barrel O.D. for the same size signal contact per MIL-C-39029. These limits must be maintained for connector applications which use rear insertion, rear release contacts in order for the standard contact insertion/extraction...

Table 4: SSBP Connector / Contact Applications and Cable Accommodations

Special Applications Although the focus for SSBP applications is on full interchangeability with MIL-C-39029 contacts used in standard multi-contact connectors, plausible special applications are encouraged. One current special application referenced earlier involves MIL-DTL-83513 Micro-D connector envelopes. A standard envelope Micro-D 25 contact cable plug and a special PC End Launch receptacle (with two mounting lugs for firm attachment to a PC board) are each fitted with insulators that accept six (6) Size 20HD SSBP coaxes. The cabled socket coax used in the Micro-D plug is the same coax...