Sunday, September 28, 2008

RF Connectors

An RF connector is an electrical connector designed to work at radio frequencies in the multi-megahertz range. RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission line impedance at the connection. Mechanically they provide a fastening mechanism (thread, bayonet, braces, push pull) and springs for a low ohmic electric contact while sparing the gold surface thus allowing above 1000 reconnects and reducing the insertion force. Research activity in the area of radio-frequency (RF) circuit design has surged in the last decade in direct response to the enormous market demand for inexpensive, high data rate wireless transceivers.


Many coaxial connector types are available in the RF and microwave industry, each designed for a specific purpose and application. Much of the development of the smaller connectors that perform well into the GHz and millimeter wave range has been conducted by test equipment measurement companies. One of their considerations is the number of connect-disconnect cycles that a connector pair can withstand while still performing as expected.

The connectors can be arranged into three categories:

Primary Interconnects - widely used to interconnect RF equipment and components,

Less Common Interconnects - connectors that are used to interconnect RF equipment and components, but are less widely in use.

Connectors for Precision Measurement Systems - which, as the title implies, are usually found only interconnecting and mating to measurement apparatus such as spectrum and network analyzers. Radio Amateurs may run across precision measurement connectors when buying flea-market items because those items are useful in microwave interconnection even though they were originally intended for measurement systems.

Sunday, September 14, 2008

Couplers (Microwave Components )

Couplers are of electronic device that joints two electronic circuits or sockets

  • In an electronic device there are many types of couplers which are known as acoustic couplers

  • In telecommunication device known as a directional coupler
  • A kind of laser mirror known as an output coupler.
  • A connector between two moving parts to relay the motion, such as a Universal joint or an Oldham coupler.
Acoustic couplers:- In these types of couplers transmission of digital data is permitted between modem of computer terminal and telephone line in either direction without making direct connections.

Directional coupler:-This types of couplers have four parts in which one is as input ,one is as 'through port where most of incoming signals exists ,one is considered as coupled port where a fixed fraction of input signals appears mostly in dBs and an isolated port which is usually terminated. If
the signal is reversed so that it enters in “through port”, most of it exits the "input" port, but the coupled port is now the port that was previously regarded as the "isolated port". The coupled port is a function of which port is the incident port.

Output coupler:-
An output coupler is a partially reflective mirror which is used in lasers to extract a portion of laser beam from the optical resonator.

Oldham coupler:-

Through this torque is transferred between two parallel,It has three discs , one coupled to input , one to the output and middle disc is joined to the first two by torque and groove .The Torque and groove on one side is perpendicular to the torque and groove on other .These types of coplers are most compact .

The coupler is named for John Oldham who invented in Ireland in 1820.


Features

  1. High Performance
  2. Power Uniform Distribution and 90°Phase Difference Type
  3. Miniature and Lightweight
  4. Couplers with SMA Connectors
  5. Equipped with Tabs
  6. High Power Type

High Performance:-

The high frequency characteristics of couplers feature extremely low loss, a high degree of matching, and high isolation.



Power Uniform Distribution and 90°Phase Difference Type:-

In this coupler has one input, two output (or two input, one output) power uniform distribution type having a 90°phase difference between the two outputs (or two inputs).


Miniature and Lightweight:-

Corrosion-resistant aluminum is used in the couplers for the case and some manufacturers has original pattern design of these type of couplers Which uses a stripline triplate method enables the couplers to be miniature and lightweight?



Couplers with SMA Connectors:-

Use of SMA connectors which feature stainless steel for the exterior Cladding makes these couplers durable.


Equipped with Tabs:-


Tabs permit direct mounting to surface circuits in the couplers



High Power Type:-

This type of coupler can be used with up to 100 W of power



Applications:-

  • Couplers can be used in mobile phones base stations
  • Measurement equipment
  • Radio communication equipment
  • Couplers as a communication tool can be vital for the public safety and security services in a critical mission".
  • Any untrained staff can use these types as these are so simple Antenna couplers





Friday, September 5, 2008

Microwave Terminations

A termination for a high-temperature superconductive thin-film microwave device formed on the one side of a substrate with the reverse side of the substrate having a ground plane. The termination can include a thin-film resistor being integral with an operative component, with the substrate being a preselected dielectric substrate. The resistor can have an epitaxially-formed layer of molybdenum metal of a first preselected thickness on the obverse side, and an epitaxially-formed layer
There are different type of Terminations
  • Non-reflective Terminations (BNC)
  • Non-reflective Terminations (SMA Type)
  • Stripline Non-reflective Terminations (Externally Mounted)
  • Stripline Mounting Non-reflective Terminations
  • DC to 65 GHz HV Coaxial Connector Plug Terminations
  • Feed-through Non-reflecting TerminationsNon-reflective Terminations (N, TNC, SSMA, POB, FL, and PO6)

Features:-

  • Wide Band width
  • high ImpedenceHigh
  • Frequency matching technique
  • High Performance
  • Equipped with SMA connector-which are of stainless steel for exterior
  • strpline external mounting type
  • High degree of matching type and economically type(VSWR of 1.05 max from DC to 8 Ghz and VSWR of 1.25 or less from 8 to 12.4 Ghz are available
  • Equipped with Tabs
  • Housing functions as a radiator to permit small size and high density mounting
  • Coupling Stress is reduced
  • High Realiability

Applications:-

  • Mobile phones base stations
  • Measurement equipment
  • Radio communication equipment
  • Dummy load for coaxial type circulators
  • Directional couplers
  • Hybrid dividers
  • Optical Transmission devices
  • Network Analyzer
  • FWA(Fixed wireless)Access
  • Measurement purposes requiring frequency up to 65GHz