Microwave Components – 915MHZ & 2.45 GHz
Waveguides & flanges A waveguide is a hollow metal structure that allows the transmission of the electromagnetic waves. Sairem offers standard waveguides at 2.45 GHz, i.e. WR284, WR340 and WR430 and at 915 MHz, i.e. WR975, with or without flanges.
Impedance tuners
An impedance tuner is a section of waveguide usually placed between the microwave generator and the applicator used to help optimizing the transfer of energy from the source to the load. Sairem makes impedance tuners that can be operated manually or automated.
Sliding short-circuits
A sliding short circuit is a waveguide-based component used in tuning applications for the adjustment of the resonance frequency of a monomode cavity; the sliding short circuit can be also used in connection with a hybrid T for the tuning of microwave applicators at high power. Sairem sliding short circuit features an innovative quarter wavelength non-contact movable short.
Directional couplers
The directional coupler is a waveguide device that should be placed between the microwave generator and the applicator/cavity to measure the incident and/or reflected power. The essential feature of the directional coupler is that it can only couple power flowing in one direction. Power entering the output port is coupled to the isolated port but not to the coupled port.
The N-type connectors of Sairem’s dual directional coupler must be connected to a 2-probe milliwattmeter for the simultaneous measurement of incident and reflected power.
Waveguide to coaxial transitions
The function of a coaxial to waveguide transition (adaptor) is to transfer the microwave signal from a waveguide to a coaxial applicator or from a coaxial signal to a waveguide structure. This adaptor has been developed for laboratory and industrial applications up to 300 W at 2450 MHz. The integrated crossbar design allows for an optimized response over a wide frequency band as well as the dissipation of heat from the core of the coaxial cable. The adaptor is tuned for working with a waveguide applicator if the microwave energy is provided from a coaxial exit (for example, Sairem’s solid state microwave generator GMS200W) or vice versa.
Dummy loads/Water loads or Dry loads (air)
The role of a dummy load is to absorb the microwave power without giving any reflected power. The dummy load is very often used in connection with a circulator – to absorb any reflected power created within the applicator, or at the end of a waveguide to absorb all incident power in transmission applications.
The dummy load can be used to measure/calibrate a microwave generator by standard calorimetric methods or for direct measurements using a milliwattmeter connected to the calibrated N-type plug.
Industrial Microwave windows
The role of the microwave quartz or PTFE window is to transfer the microwave energy between two media without inducing any reflected power. The window allows the separation of different environments at pressure close to atmospheric; in addition, the PTFE window can be used as a ‘light barrier’, i.e. hides the light emitted by plasma that could trigger off the arc detector installed in some microwave generators.
Twists, bends E & H plans
These waveguide components allow changing the direction of the waveguide port; they can be equally used for polarization purpose.
