Deliverable 10.2: Report on the results of the transmitting/receiving antenna beam matching
Antenna compression techniques for atmospheric/ionospheric radar applicationsare used to be able to transmit wide beams with all the available transmitted power.
In most of applications, such schemes should be accompanied by aperture synthesis imaging techniques that will allow resolving space and time ambiguities within the wider beams. Depending on the target of interest and system capabilities, one can apply binary phase coding or parabolic phase fronts.
Here are some specific recommendations or important points to consider for the EISCAT_3D:
- If the target of interest has long correlation times, then complementary binary phase coding could be used. Its practical implementations will depend on the actual antenna geometry used. If the EISCAT_3D transmitting antenna is a square array, then the same procedure used in Woodman and Chau  can be implemented, if not, similar procedures need to be developed.
- Parabolic phase fronts are the most recommended procedure if the system allows phase changes with good precision. If the target of interest is very strong (more than 2-30 dB SNR) and small compare to the illuminated volume, then only phase changes are needed. On the other hand, if a very smooth wide beam is needed (e.g., for volume-filling type of targets, or weak targets), then amplitude modulation with good precision is needed on transmission.
- Fast changes in phase and amplitude are needed (from IPP to IPP) to allow changing the beam shape very rapidly.
- The maximum beam width that one can achieve will be limited by the minimum size of the antenna module that can have phase changes. For example in the case of Jicamarca, this minimum unit is a module consisting of 12x12 dipoles, then the maximum beamwidth that one can achieve is determined by the beamwidth of the module, i.e., ~8 degrees (HPBW).