Opportunity
The measurement of antenna gains becomes more difficult as the operating frequency increases. Conventional methods require rotation of antenna probes or antennas under test (AUT). However, the rotating mechanics significantly increases the complexity of the entire measurement system and the rotation of the antenna is very hard to realize with the absence of high-frequency rotation joints. In addition, at millimeter-wave and terahertz range, frequency extenders are usually required as part of the measuring equipment. What’s worse, mechanical rotation would potentially damage frequency extenders which are fragile and extremely expensive. The invention describes a rotation-free far-field gain measurement method of linearly-polarized (LP) antennas. This method uses an LP antenna probe, a circularly-polarized (CP) antenna probe and an LP standard-gain antenna to obtain the co-polarization and cross-polarization gains of the AUT, thus alleviating problems as described earlier.
Technology
To achieve rotation free measurement, two types of antenna probes are needed for the measurement, which are a linearly-polarized (LP) antenna probe and a circularly-polarized (CP) antenna probe. The LP antenna probe is required to have cross-polarization level that is small enough to be omitted. The CP antenna is built with adding a polarizer in front of a LP antenna. Four measurement steps are taken to get the co-polarization and cross-polarization gains of the antenna under test, which are the amplitude of the forward voltage gain between the CP antenna probe and the LP standard-gain antenna ,the amplitude of the forward voltage gain between the CP antenna probe and the antenna under test , amplitude of the forward voltage gain between the LP antenna probe and the LP standard-gain antenna and the amplitude of the forward voltage gain between the LP antenna probe and the antenna under test. With these arrangements, radiation pattern of the antenna under test could be mapped by changing the relative position and angle between the receiving and transmitting antennas during measuring process.
Advantages
- The invention presents a novel antenna gain measurement method which requires no rotation to the antenna feed or probe. This greatly simplifies the measuring process and system complexity. In addition, in the antenna measurement of very high frequency range where frequency extenders are used or rotary joints are unavailable, rotation of antenna probe or feeding components becomes infeasible and poses potential damage to the fragile and expensive equipment. In this case, the invention will be the only feasible solution for antenna gain measurement.
Applications
- The invention provides a general antenna measuring method at a fundamental level. It can integrate easily to the existing antenna measurement equipment and software of any antenna makers.
