Transcription of MICROWAVE COAXIAL CONNECTOR TECHNOLOGY: A …
1 2900 inland Empire Blvd. Ontario, California 91764-4804 Tel: 909-987-4715 Fax: 909-987-1112 MICROWAVEC opyright 2000 Maury MICROWAVE Inc., all rights reserved. SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICEMICROWAVE COAXIAL CONNECTOR TECHNOLOGY: A CONTINUING EVOLUTION application note5A-021 Page 1 of 2113 Dec 2005application noteIntroductionCoaxial connectors are one of the fundamental toolsof MICROWAVE technology and yet they appear to betaken for granted in many instances. Unfortunately,many engineers tend to overlook the lowly connec-tor with resulting performance compromises in theirapplications. A good understanding of connectors ,both electrically and mechanically, is required toutilize them properly and derive their full benefit. Itshould be remembered that performance starts at connectors provide a means to connect anddisconnect transmission lines, components and sys-tems at MICROWAVE frequencies.
2 They allow accessingcircuits, modularizing, testing, assembling, inter-connecting and packaging components into is a broad variety of COAXIAL connectors avail-able today due to the various design trade-offs andapplications that exist at MICROWAVE frequencies,including impedance (usually 50 ohms), frequencyof operation, power handling, insertion loss, reflec-tion performance, environmental requirements, size,weight and connectors have played a major role in theevolution of MICROWAVE COAXIAL CONNECTOR technol-ogy, as shown in Figure 1. It is through theseconnectors that our measurement equipment hasimproved and thereby connectors , in general, haveimproved. The foresightedness of the and IEEEP287 CONNECTOR committees in the early 1960s gaveus the philosophies and concepts and paved the wayto solutions for the fabrication of precision connec-tors that are in use today. The IEEE P287 committeehas been re-activated and is carrying on this impor-tant work (see IEEE P287 Committee).
3 Figure 1: Precision COAXIAL connectors in use today;(a) 7mm and 14mm sexless connectors and (b) femaleand male, type N female and paper provides a brief history of COAXIAL connec-tors, gives an overview of COAXIAL connectortechnology today, cites sources of further informa-tion and takes a look into the future as connectorscontinue to P287 CommitteeIn 1988, the sub-committee P287 for precision co-axial connectors under the IEEE/Instrumentation andMeasurement Society was re-activated by the IEEES tandards Board to carry on the work originallybegun in objective of this committee was to revise IEEES tandard 287 published in 1968 so that it representsthe current state of the art in precision connectortechnology; to standardize both laboratory precisionconnectors (LPC) and general precision connectors (GPC) in a minimum number of transmission linesizes covering the frequency range from DC to 110 GHz; to standardize the means for transferring labo-ratory measurements to devices with field type con-(a)(b)Originally published as a Feature Article in the MICROWAVE Journal 1990 State of the Art Reference, September 1990; Updated December 2005 Mario A.
4 Maury, MICROWAVE CorporationSPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE2900 inland Empire Blvd. Ontario, California 91764-4804 Tel: 909-987-4715 Fax: 909-987-1112 note5A-021 Page 2 of 2113 Dec 2005nectors; to produce a standard that is useful andmeaningful to the manufacturers and users of preci-sion COAXIAL connectors ; and to incorporate any otheritems deemed relavant and appropriate into the committee is in the process of updating thestandard that currently covers 7mm and 14mm sex-less precision connectors . In addition, it has adoptedpin socket type connectors in the line sizes andprecision type N connectors for standardization,shown in Table committee is chaired by Harmon Banning of Gore & Associates, Newark, Delaware and con-sists of 25 members who provie a broad cross sectionof the MICROWAVE and Definitions ofCoaxial ConnectorsThere are basically two distinct categories of con-nectors, sexless and sexless CONNECTOR is a CONNECTOR where both halvesof the CONNECTOR mated pair are identical.
5 They arecoplanar. The outer conductor coupling mechanismand the center conductor contacts are captive to theindividual halves. There are sexed outer conductorcoupling versions of sexless connectors . For ex-ample, 7mm GPC connectors typically are limited toprecision connectors . These also are referred to ashermaphroditic connectors have a female and a male configu-ration to form a mated pair. They can be coplanar ornon-coplanar, and generally are sexed in both con-ductors. Type N and SMA connectors are examplesof sexed connectors . This is the predominant cat-egory of connectors in use type of CONNECTOR refers to a specific connectorconfiguration that forms the basis of a family ofconnectors that mate with each other. For example,types N, BNC, SMA and are a family. It is alsopossible to have mating between families, for ex-ample, SMA and , and are three grades of connectors ; production,instrument and metrology.
6 The production grade ofconnectors includes general purpose or field con-nectors for components and cables. The emphasisshould be one assembly simplicity and low instrument grade of connectors includes preci-sion or test connectors for use with test andmeasurement equipment, meeting high performancestandards, that is, low reflection and good repeat-ability, and moderate metrology grade of connectors include highprecision connectors primarily used on measure-ment standards where the highest accuracy is requiredand would allow traceability to national cost of these connectors is it would be difficult for all connectors tomeet this criteria. However, most can at least bemade to meet production and instrument grade. Newconnectors, as they are designed, should follow thesegeneral is the mechanical configuration (dimen-sions and tolerances) of a CONNECTOR mating propertiesthat must be clearly defined in order to insure me-chanical mating compatibility and electricalrepeatability.
7 Different dielectrics present at theinterface include air dielectric and dielectric simplifies CONNECTOR construction andgenerally is used on precision connectors so accu-rate standards can be created. These connectorsinclude type N, 7mm and Size (mm)TABLE 1 Adopted Pin Socket Type ConnectorsMaximum Frequency (GHz)2900 inland Empire Blvd. Ontario, California 91764-4804 Tel: 909-987-4715 Fax: 909-987-1112 MICROWAVEC opyright 2000 Maury MICROWAVE Inc., all rights reserved. SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE application note5A-021 Page 3 of 2113 Dec 2005A solid dielectric like teflon usually is used and thereare two basic configurations, flush and connectors are SMA and SSMA; and overlap-ping connectors are BNC, TNC, C and constructions generally are used forhigher power application and to prevent plane is the outer conductor mating planeof a COAXIAL CONNECTOR .
8 It is desirable to have boththe outer and center conductors coplanar at thisplane, that is, in the identical plane, for electricaland mechanical connectors are connectors where the cen-ter and outer conductor mate in the same connectors include 7mm, SMA and coplanar connectors are connectors where thecenter conductors don't mate in the same connectors include N, BNC, C and type describes how the outer conductorsare connected. There are basically three types,threaded, twist or bayonet locks and snap-on. TypeN, TNC, SMA and 7mm are threaded; type BNC andC are twist locks; and SMB is a sexed connectors are of the pin-and-socket type,where there is a male contact (pin) and a femalecontact (socket). There are currently two types offemale contacts slotted and slotless, used for preci-sion applications. N, BNC, SMA and meetthis COAXIAL connectors are COAXIAL con-nectors for use above 18 GHz.
9 The term is appropriatebecause they operate in the mm-wave region. Gen-erally these are pin-and-socket type connectors , suchas SMA, and Sexless connectors alsohave been made above 18 a general rule, a COAXIAL CONNECTOR 's electricalperformance (SWR and insertion loss) must be de-fined based on a mated CONNECTOR pair since this isthe only way they can be measured; this is particu-larly true of non coplanar are many ways to describe connectors andusually a combination of these terms is following two important equations are helpful indefining COAXIAL CONNECTOR parameters1, impedance, D Z = ln ( ) dcutoff frequency (TE11), 7512 fc = (GHz) (d + D)whereD=outer conductor inner diameterd=center conductor outer diameter =the dielectric constant in transmission lineair= = predominant impedance of COAXIAL connectorsused is 50 (see Why 50 connectors ?)
10 CONNECTOR electrical specifications are sometimesdifficult to specify or verify because their perfor-mance depends on how they are assembled to thetransmission line media, that is, flexible cable,stripline or microstrip. The only connectors that canbe accurately specified are connectors for mountingor rigid COAXIAL covered in this paper are generally lim-ited to those developed or in primary use in theUnited States. Also all dimensions are in inchesunless otherwise helpful hints are: use the largest coaxialtransmission line and CONNECTOR possible for yourapplication, as this will provide the best perfor-mance; check the manufacturer's specifications (bothmechanical and electrical), sometimes they are bet-SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE2900 inland Empire Blvd. Ontario, California 91764-4804 Tel: 909-987-4715 Fax: 909-987-1112 Dec 2005application note5A-021 Page 4 of 21ter than military specifications and sometimes theyare worse; and define the CONNECTOR early in theproject, not at the end of 50 connectors ?
