RF Waveguide Components Information
RF waveguide components are circular, elliptical or rectangular metal tubes or pipes through which electromagnetic waves are propagated in microwave and RF communications. The wave passing through the medium is forced to follow the path determined by the physical structure of the guide. RF waveguide components may, under certain conditions, contain a solid or gaseous dielectric material. They can also be implemented on the surface of a printed circuit board, as is the case for coplanar waveguides. Typically, RF waveguide components are made from aluminum, brass, bronze, copper, or silver. They vary in terms of both operating frequency and voltage standing wave ratio (VSWR), a unitless measurement from one to infinity that expresses the amount of energy at the input or output of the device. The Electronic Industry Alliance (EIA) approves sizes for RF waveguide components.
A variety of RF waveguide components are available. Attenuators reduce signal power levels by the gain with little or no reflection. Bulkhead feedthroughs extend waveguides through pressurized walls or cabinets. Circulators are passive devices with three or more ports that allow the signal entering each port to pass to an adjacent port. Couplers sample frequency transmissions by grouping signals asymmetrically. Combiners accept several input signals and produce a combined output signal. Dividers accept an input signal and deliver multiple outputs that are equal in phase and amplitude. Isolators permit a signal to pass in one direction while providing high isolation to reflected energy in the reverse direction. Transition adapters connect waveguide components of different cross-section sizes. Polarizers change wave polarization, the orientation of the electric field vector. Pressurizing sections inject air or gases and pressure windows seal RF waveguide components. RF rotary joints or couplers and sliding short circuits are used in a variety of RF and microwave techniques. Other RF waveguide components include waveguide filters, switches, tees, tuners, and amplifiers.
There are several types of assemblies for RF waveguide components. Bend assemblies are used to change the direction of the electric or magnetic field lines inside waveguide systems. Twist assemblies are used to change the polarization of the radio waves inside the waveguide. Straight section assemblies are RF waveguide components used for straight transition between waveguides. Offset section assemblies are used to connect two non-aligned waveguides. Custom assemblies are waveguide components made according to customer instructions.
Flanges connect waveguide sections to one another or terminate RF waveguide components. They can have a rectangular, circular, or square profile and plating made of cadmium, nickel, rhodium, silver, or tin. Several flange types are available. Basic types include union guide (UG) flanges and connector pressurized rectangular (CPR) flanges. UG is the military standard MIL-DTL-3922 for a range of flange types. UG variants include cover or plate and choke flanges. CPR variants include miniature (CMR), grooved (CPRG), and flat (CPRF) flanges.