There is significant speculation in the PLA watching community as to the precise role of the Y-9LG/High New 13. The current prevalent suggestion is a role focused on electronic warfare, notably a role as jammer platform including such use of the “balance beam” style AESA. Factual data to confirm a particular role remains absent. As usual PLA does not comment on roles and capabilities especially of their newest systems in service. Consequently, assessments are limited to observable characteristics, unit affiliation and the character of deployments.
Personally, I suspect this new configuration is an enhanced AEWC system, which additionally incorporates significant EW capability. Such a design seems in line with the overall trend of AESA development not just accommodating detection and tracking of relevant targets cueing effectors, but additionally suppressing them through means of electronic warfare. The latter is an inherent strength of modern AESA type radars and as such utilised also by foreign air forces elsewhere. Increased flexibility engaging in electronic warfare is a primary demand on new developments globally.
Additionally, such an enhanced AEWC system would be in line also with PLA-developments including the earlier KJ-500 (High New 10), also present in Thailand. KJ-500 already incorporated ELINT capability seen in other designs such as the Y-8JZ (High New 8). Some aspects of the new Y-9LG configuration, especially the large rectangular panels on the rear airframe, were first observable on the Y-9Z aka High New 12. The development dynamic on display therefore appears to mirror the earlier efforts in AEWC and overall ELINT/EW-development.