So far we have discussed how to design various external and internal antennas. After making a prototype, the next thing to do is to evaluate the antenna's performance. In the process of designing an antenna, there are two kinds of antenna measurements: passive and active measurements. The passive measurements evaluate the performance of an antenna when the host device is inactive, so some means of external signal generators must be used. The passive measurements include VSWR or reflection coefficient, efficiency, gain, and so on. The active measurements evaluate the performance of an antenna when it is installed in a working device. Measurements, such as total radiate power (TRP), effective isotropic radiated power (EIRP), total isotropic sensitivity (TIS), effective isotropic sensitivity (EIS), and so on, all belong to this category. After an antenna design is rolled out to an assembly line, then various production tests are carried out. Passive production tests are carried out by antenna vendors and active production tests are implemented by phone manufacturers.
5.1 Passive Antenna Measurement
5.1.1 Measurement on a Vector Network Analyzer
The network analyzer is a piece of equipment which can measure a wide variety of parameters, such as reflection coefficient, transmission loss, and so on. The scalar network analyzers (SNA) can only measure the amplitude of various parameters. SNAs are relatively cheaper and are widely used in production lines. ...