In wireless communication, the transmit and receive antennas are connected to the radio through a transmission line. This transmission line is usually a coaxial cable or waveguide. This connection system is referred to as a transmission feed line system. Figure: A Typical Transmission Feedline System shows an example of a typical transmission feed line system.
A Typical Transmission Feedline System
The performance of a transmission feed line system may be affected by excessive signal reflection and cable loss. Signal reflection occurs when the RF signal reflects back due to an impedance mismatch or change in impedance caused by excessive kinking or bending of the transmission line. Cable loss is caused by attenuation of the signal as it passes through the transmission line and connectors. To verify the performance of the transmission feed line system and analyze these problems, three types of line sweeps are required:
