A termination is a one-port device with an impedance that matches the characteristic impedance of a given transmission line. | TERMINATIONS DUMMY LOADS A termination is a one-port device with an impedance that matches the characteristic impedance of a given transmission line. It is attached to a certain terminal or port of a device to absorb the power transmitted to that terminal or to establish a reference impedance at that terminal. Important parameters of a termination are its VSWR and power handling capacity. In a receiver terminations are usually placed at various unconnected ports of components such as hybrid and power dividers to keep the VSWR of the signal path low. It is extremely important that the isolated port in a directional coupler and the unused port of a power divider . only three ports of a four-way power divider are used be properly terminated. All of the design considerations of directional couplers and power dividers are based on the fact that all ports are terminated with matched loads. If an unused port is not properly terminated then the isolation between the output ports will be reduced which may severely degrade the performance of the receiver. A termination is the terminology used to refer to a low power single terminal device intended to terminate a transmission line. Similar devices designed to accommodate high power are generally termed dummy loads. TERMINATIONS Terminations are employed to terminate unconnected ports on devices when measurements are being performed. They are useful as dummy antennas and as terminal loads for impedance measurements of transmission devices such as filters and attenuators. The resistive elements in most terminations are especially fabricated for use at microwave frequencies. Two types are commonly employed 1 resistive film elements and 2 molded resistive tapers. The resistive film is very thin compared to the skin depth and normally very short relative to wavelength at the highest operating frequency. The molded taper consists of a dissipative material evenly dispersed in a properly cured dielectric medium. Both forms of .
