Frankly I disagree. Size of the bulbs has nothing to do with progress or what's really inside the bulb, which also has to be shaped for hydrodynamic reasons. You need smaller MF/HF sonars in littoral, brown water and heavily crowded environments for better differentiation; larger LF sonars in open ocean for range. Given the sea conditions the PLAN faces, one can see a greater need for HF/MF sonars.
The fact there is Chinese progress on sonars can be seen on the submarines, as pretty much since the 1990s, the subs have gone indigenous with large LF passive flank sonars---first tested on the Hans, Mings and the first Song---as well domed bow sonars that are big enough to fit the bow domes of the Shang, Yuan, and Jin class, and on the refits of the improved Han and Xia. The passive sonars on the Yuan deserve mention for having an unusual layout, four unevenly spaced arrays, compared to the standard three evenly spaced arrays, an indication that the Yuan's flank sonars are a different design than Song's, Shang's, Jin's and the improved Han's. Latest pictures now point to a new TAS on the tails of the subs. New developments on torpedoes, such as the Yu-6 and Yu-7, also point to progress, as well as new sea mapping and research ships, such as the new SWATH ship seen lately.
What about "design" of the sonar? The really important thing about the sonar is the hydrophones and the electronics behind them. Basically the mechanical part of the sonar is a dome, cylinder, or sphere with lots of holes where the hydrophones are set. Nothing really mystical about it, like in the sense there is nothing mystical about a UHF/VHF radar antenna.
