GPO, GPPO and G3PO Application Notes Corning Gilbert s push-on connector products allow users flexibility in modular and board layout (in high density situations), frequency bandwidths from DC to 100 GHz and ease of mating or de-mating using female cable adapters or blind mate interconnects (bullets) while achieving a highly reliable electro/mechanical interface. High quality and cost effectiveness make Corning Gilbert the push-on connector of choice. The GPO male interface is compliant to MIL-STD-348, and it is in accordance with MIL-PRF-39012a and DESC 94007/94008. I. Materials and Finishes The following information represents the material/plating used in the manufacturing of push-on male shrouds (soldered, braised or threaded), blind mate interconnects (bullets), straight female cable connectors, flange/bulkhead connectors and a wide assortment of adapters. Table 1-a Material Specification BeCu (Beryllium Copper) ASTM B 196 and/or ASTM B 197 Brass ASTM B 36, B121, B16, B16M Stainless Steel (303/304) ASTM A484/ A582 or A555/581 Kovar ASTM F15 Note: BeCu is the common metal used for all contacts. Table 1-b Finishing Specification Gold (50-100u in.) ASTM-B488 Type 1, Class 1.25 Nickel (50-100u in.) AMS-QQ-N-290 Table 1-c Dielectric Specification Virgin PTFE Flourocarbon ASTM D 1710 and ASTM D 1457 Torlon (Polyamide-Imide) ASTM-600/700 PEEK ASTM D 500, 600 & 700 Tefzel ASTM D-500, 600 & 700 II. Mechanical Detent: a mechanism that temporarily keeps one part in a certain position relative to that of another, and can be released by applying force to one of the parts. Each of the detent levels Full Detent, Limited Detent and Smooth Bore provide different levels of force required to mate and de-mate the connectors. The following table shows available detents, typical engagement and disengagement forces, and mating cycles for GPOs, GPPOs and G3POs. Table 2-a Engage and Disengage Forces (All values are shown in lbs.) Engage Disengage Cycles (Min) Detent GPO GPPO G3PO GPO GPPO G3PO GPO GPPO G3PO Full 7.0 6.5 4.2 9.0 4.5 2.2 100 100 100 Limited 5.0 N/A N/A 7.0 N/A N/A 500 N/A N/A Smooth Bore 2.0 2.5 1.2 0.5 1.5 0.9 1000 500 500 Note: Corning Gilbert recommends a Full Detent when used in conjunction with a female cable connector. Smooth Bore and a Full Detent male shroud are recommended when using a blindmate (bullet) to interface two modules (mated together) or printed circuit board in a stacked configuration. Corning Gilbert, Inc. Microwave Push-on Interconnects 159
Axial Misalignment: a distance the female interconnect can travel in an axial direction from the reference plane with minimal effect to the VSWR response. See Figure 1 and Table 2-b. Swept VSWR versus various axial misalignment data can be found on Charts 1, 2 & 3. Figure 1 Visual Concept of Axial Misalignment Ideal Misaligned Table 2-b Axial Misalignment from Reference Plane vs. VSWR for GPO, GPPO & G3PO Interface Axial Misalignment VSWR (Typ) GPO (26.5 GHz) Full/Limited Detent.010 max 1.10:1 Smooth Bore.018 max 1.30:1 GPPO (40 GHz) Full Detent.010 max 1.15:1 Smooth Bore.012 max 1.30:1 G3PO (65 GHz) Full Detent.008 max 1.20:1 Smooth Bore.010 max 1.35:1 Chart 1 GPO Interface (A1A1-0001-01) Axial Misalignment from Reference Plane vs. VSWR @.001 Increments 160 Corning Gilbert, Inc. Microwave Push-on Interconnects
Chart 2 GPPO Interface (B1B1-0001-01) Axial Misalignment from Reference Plane vs. VSWR @.001 Increments Note: Surpassing the axial misalignment of.010 (+/-.005 ) will affect the VSWR. When using a male Full Detent shroud to a bullet, to a Smooth Bore male shroud, tests show that a.018 (+/-.009 ) misalignment would result in a VSWR of 1.3:1 (typical). Radial Misalignment: the amount of radial deflection a bullet can travel without affecting mechanical performance of both the bullet and male shroud. See Figure 2 and Table 2-c. Swept VSWR versus radial misalignment can be found on Charts 3 & 4. Figure 2 Visual Concept of Radial Misalignment Ideal Misaligned Radial Misalignment and Bullet Length When using a bullet between GPO/GPPO/G3PO male shrouds, the amount of radial misalignment will depend on the length of the bullet, with respect to the male shroud. Corning Gilbert standard bullet was used for the following tests. Table 2-c Radial Misalignment from Centerline Reference Plane vs. VSWR for GPO, GPPO & G3PO Interface Radial Displacement VSWR (Typ) GPO +/-.010 1.10:1 GPPO +/-.010 1.35:1 G3PO +/-.008 1.40:1 Corning Gilbert, Inc. Microwave Push-on Interconnects 161
Chart 3 GPO Interface (A1A1-0001-01) Radial Misalignment from Centerline Reference Plane vs. VSWR @.001 Increments Chart 4 GPPO Interface (B1B1-0001-01) Radial Misalignment from Centerline Reference Plane vs. VSWR @.001 Increments 162 Corning Gilbert, Inc. Microwave Push-on Interconnects
III. Electrical Table 3-a General Product Specifications Parameter GPO GPPO G3PO Insulation Resistance (IR) 5,000 Mohms @ 500 Vdc 5,000 Mohms @ 500 Vdc 3,700 Mohms @ 250 Vdc Dielectric Withstanding Voltage (DWV) 500 Vrms 325 Vrms 250 Vrms RF High Pot. @ 5 MHz 325 Vrms 200 Vrms 150 Vrms Corona Level @ 70,000 ft 190 Vrms 125 Vrms 100 Vrms Center Conductor Contact Resistance (mohms max.) 6.0 6.0 6.0 Center Contact Retention (captivated center conductor) 1.5lbs min 1.5lbs min.75 min Temperature Range -65 to +165º C Yes Yes Yes Average Power Ratings in Watts See Chart 5 See Chart 5 See Chart 5 Chart 5 Average Power Handling Ratings for GPO, GPPO & G3PO and Typical De-rating Factors for Temperature/Altitude GPO GPPO G3PO Corning Gilbert, Inc. Microwave Push-on Interconnects 163
VSWR Characteristics of a Blindmate Interconnect (Bullet) Figure 3 Standard Bullet Mated Between Two Male Shrouds Note: The bullet is bottomed out against male shrouds. This is the ideal case. Table 3-b Blind Mate (Bullet Mated to Male Shroud) Parameter GPO GPPO G3PO Impedance (ohms) 50 50 50 Frequency (GHz) 26.5 40 65 VSWR (Typ) 1.15:1 1.15:1 1.1:1 to 26.5 GHz 1.25:1 to 65 GHz Chart 6 GPO Blindmate Interconnect (Bullet) Chart 7 GPPO Blindmate Interconnect (Bullet) 164 Corning Gilbert, Inc. Microwave Push-on Interconnects
Chart 8 G3PO Blindmate Interconnect (Bullet) VSWR Characteristics of GPO, GPPO & G3PO Female Straight to Flex or Semi-rigid Cable Figure 4 Female Straight to Flex or Semi-rigid Cable (GPO Example) Table 3-c VSWR Performance for GPO, GPPO & G3PO Female, Straight Cable Connectors Parameter GPO GPPO G3PO Impedance (ohms) 50 50 50 Frequency (GHz) 26.5 40 65 VSWR (max) 1.10:1 1.10:1 to 26.5 GHz 1.10:1 to 26.5 GHz 1.20:1 to 40 GHz 1.25:1 to 65 GHz Note: The above data was generated using two female straight connectors with a length of coax in between. Corning Gilbert, Inc. Microwave Push-on Interconnects 165
Chart 9 GPO Female Straight Connector Chart 10 GPPO Female, Straight Connector Surface Mount GPO Connector to Microstrip Matching Figure 5 GPO Surface Mount Connector on Rogers 4350 10mil Thick Substrate Material Structure Visualization Note: This illustration shows how a GPO SMT connector (A012-P93-01) is mounted and matched on microstrip using Rogers 4350 10-mil thick substrate. 166 Corning Gilbert, Inc. Microwave Push-on Interconnects
Figure 6 GPO Microstrip Footprint Note: Footprint of the printed circuit traces and the plated hole positions and pre-plate diameters shown above. Figure 7 Modeled Structure (structure simplification for modeling) Note: Shows how the GPO SMT connector is modeled for simulation using SCT Microwave Studio software. Chart 11 Input & Output Return Loss Results Corning Gilbert, Inc. Microwave Push-on Interconnects 167
Chart 12 Forward & Reverse Insertion Loss Results Note: Forward and reverse insertion losses versus frequency shown above. Surface Mount G3PO Connector to Microstrip Matching Figure 8 Structure Visualization Note: Mounting of a G3PO connector on Rogers 4350B microstrip with a dielectric thickness of 10 mils (0.010 inches). The dielectric constant of the substrate is 3.48±.05. The copper upper layer is assumed to be ½ ounce copper plated up to 2 ounce copper total (2.7 mils or 0.0027 inches thick). Figure 9 Structure Simplification for Modeling Note: This simulation was simplified by setting the output to a standard 50 ohm coaxial line. The remainder of the structure matches the G3PO surface mount connection exactly. The reference plane for the plots of the S parameters is set to the beginning of the taper at the bottom of the figure. 168 Corning Gilbert, Inc. Microwave Push-on Interconnects
Figure 10 Microstrip Footprint Note: Above footprint is based on simulation data only. Footprints will vary, depending upon layout, board material and thickness. Chart 13 Simulated S-Parameters Note: The maximum input return loss within the simulated frequency range is 32.84202 db at 12.22 GHz. The maximum insertion loss was -0.09498425 at 16.28 GHz. Corning Gilbert, Inc. Microwave Push-on Interconnects 169