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Quick History



QUICK LOCK 1.0

In fact, in order to satisfy certain requirements for particular applications, quick lock connectors emerged early on the market. These can be referred to as first generation designs, and some of the more classic types are as follows:

dot2 LEMO Quick Lock version
LEMO


dot2 HIROSE-POB Design

 

HIROSEPOB



dot2 Amphenol Steel ball Design

AMPHENOL

dot2 1.0/2.3 Design
102


 

 

dot2 Updata Design of 1.0/2.3

UP102

 

 

Not withstanding that the electronic performance of these designs is far from perfect and they cannot be used in high frequency applications, they nevertheless began the RF connector process of evolution from a threaded interface to a quick locking one: paving the way for a new generation of Quick Lock designs.
 

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QUICK LOCK 2.0

In recent years, some of the top RF connector manufacturers have ushered in the second generation of quick lock connectors, and one after another competing Quick Lock design solutions have been released: including the Quick Lock Formula's (QLF) QMA and QN as well as the QLS and the SnapN. These designs have already been successful in replacing the SMA and Type N connectors in some communications equipment applications, but shortcomings in mechanical and electronic performance indexes, in addition to their relatively high cost, has led to strict limitations to the sphere of their application. These are the 2nd generation of Quick Lock Connectors:

dot2 QLF's QMA

dot2 QLS (Quick Lock Standard)

dot2 QLF's QN

dot2 SnapN 


 

QLF's QMA

The first of its kind, the QMA researched and developed by Huber+Suhner and Radiall successfully integrated a snap locking mechanism into the design(see QLF'QN), thereby allowing this quick lock SMA connector to be mated 10x faster. Other advantages over the SMA include 360º rotation of the cable after mating and greater packaging density because a torque wrench was no longer required for installation. However, like most initial leaps in technology, this early design left room for improvement:
qlf-qma

dot2 The spring lock for the QLF's QMA design requires the use of beryllium copper. This mineral, already expensive in and of itself, is also difficult to process and requires thermal as well as environmental protection treatment; which makes the overall manufacturing cost for this connector very high.

dot2 This connector has no seal. Even if intended for indoor applications, RF connectors must have a protective seal in order that its contact conductors are not exposed to the air. Even air inside a room contains moisture, gas, dust and other particles that can contaminate and corrode a connector's internal conductors and only an IP68 seal can keep them isolated from the outside environment; increasing the connector's life span and ensuring consistent electronic performance. For this reason, all of the most widely applied RF and Microwave connectors, including SMA, Type N, BNC, TNC, and 7/16, all have a waterproof seal.

dot2 The effective length of the QMA inner conductor is too short, being only 1.6 mm, as opposed to the original SMA which is 2.3 mm. Not making use of the structural parameters of the SMA, which has been tested and used by engineers for tens of years, is to go against the basic principles of industrial design.

 

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QLS (Quick Lock Standard)
 

Jointly designed and manufactured by Telegartner and IMS (both members of the QLS Alliance) this quick lock SMA connector series has very strong interface retention force at 200N, more than 3x greater than QMA, resulting in it being very difficult to break its connection accidently. However, despite this improvement, QLS offers no other real distinct advantages over the QMA:

dot2
This connector has no seal. Even if intended for indoor applications, RF connectors must have a protective seal in order that its contact conductors are not exposed to the air. Even air inside a room contains moisture, gas, dust and other particles that can contaminate and corrode a connector's internal conductors, and only an effective seal can keep them isolated from the outside environment; increasing the connector's life span and ensuring consistent electronic performance. For this reason, the most widely applied RF and Microwave connectors, including SMA, Type N, BNC, TNC, and 7/16, all have a waterproof seal.

dot2 A large number of component parts, coupled with the need for a high degree of processing accuracy, has made manufacturing the QLS both difficult and expensive.

 

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QLF's QN


In 2004, the QLF released its latest QN design(see QLF'QN figure) in which they replaced the wave spring washer from an earlier version with a radial disk spring in order to increase axial pressure, reduce contact resistance, and heighten contact stability. By using a radial disk spring rather than the wave spring washer, when the internal conductors come into contact during installation, contact is not just at a few points as before, but in a complete circle. This greatly improves its passive intermodulation performance (PIM) performance, while decreasing the VSWR and Insertion Loss.
qlf-qn

dot2 The contact surface of the male's outer conductors is tapered to a point, and this generates a relatively high axial pressure under the influence of the radial disk spring, improving the contact force. However, the space formed between the sharp end of the male outer conductor and the spring is an irregular shape, so that the characteristic impedance at this point is not continuous and will cause a rather large reflection: especially when transmitting high-frequency electromagnetic waves.

dot2 The designers did not make use of the basic structural parameters of the original Type N connector, in which the external diameter of the inner conductor is 3.04 mm and the internal diameter of the outer conductor is 7.00 mm. As a result, a great deal of time and energy went into the redesigning, retesting, and verification of the QN, and all the valuable experience accumulated over years and years of testing and working with the N type connector have been wasted. This goes against the basic principles of industrial design.


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SnapN

In 2006, Rosenberger released the SnapN, which effectively remedied the defects of the QN, preserving the original Type N's fundamental structural parameters and achieving zero clearance between the contact conductors. However:
SnapN

This connector has no seal. Even if intended for indoor applications, RF connectors must have a protective seal in order that its contact conductors are not exposed to the air. Even air inside a room contains moisture, gas, dust and other particles that can contaminate and corrode a connector's internal conductors, and only an IP68 seal can keep them isolated from the outside environment; increasing the connector's life span and ensuring consistent electronic performance. For this reason, all of the most widely applied RF and Microwave connectors, including SMA, Type N, BNC, TNC, and 7/16, all have a waterproof seal.

The contact force for the outer conductors is supplied by an internal spring. This spring in turn also determines the engagement force, which in this case is 30N, so that both the contact force and the engagement force are equal (30N). This means it would only take about six or seven pounds of outside force in the form of an impact, vibration or movement of the cable to break the contact between the outer conductors, negatively affecting electronic performance (especially the PIM). The design conflict consists of the following: if designers want to increase the contact force for the outer conductors, they have to increase the effectiveness or strength of the internal spring. In increasing the spring strength, the engagement force will increase in direct proportion. In order for this design to match the contact force of the type N connector, which is at least 200N, it would mean that it would then also take 200N in order to mate the connector. This is clearly unreasonable.

There are too many component parts for which the processing requirements are fairly complicated. As a result, the manufacturing cost for this connector is quite high.

When de-mated, the contact surface of the outer conductor is completely exposed, offered absolutely no protection by the body of the connector. In real applications, it will be very easy for minimal contact to lead to the deformation of the outer conductor, negatively affecting performance.

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