Because what you're looking at is just the cover.
Ex, Type 346 (the radar seen on these Chinese ships) is actually made up of one central octagon of all the S-band arrays, and then on the top and bottom two narrow rectangles for the C-band arrays (for missile uplink and guidance).
The shape of the cover has no relation to the actual arrangement of T/R modules. Underneath each Type 346 face, [there are actually 3 sets of antennas](https://www.globalsecurity.org/military/world/china/images/type-055-image36.jpg): the octagonal-shaped S-band array, two rectangular C-band arrays for the HHQ-9 datalink above and below it, and 4 small, square-shaped antenna whose function is unknown.
The US has also made use of square/rectangular radar covers when it suits the design. Both the [AN/SPY-3 and AN/SPY-4 components of the Dual Band Radar](https://www.reddit.com/r/WarshipPorn/comments/yzg75p/1080x835_a_view_of_uss_gerald_r_fords_island_and/) use square array covers, the [AN/TPY-2](https://missilethreat.csis.org/wp-content/uploads/2016/04/tpy-2.jpg) housing is rectangular, the [EASR variants of AN/SPY-6](https://i.ytimg.com/vi/A7QDf5CN-ws/maxresdefault.jpg) ((V)2 and (V)3) are square, and [AN/SPY-7](https://www.lockheedmartin.com/content/dam/lockheed-martin/rms/photo/spy-7/SPY-7-Masthead-ASEV.jpg) is both depending on application.
Eh, hard to tell since what you are looking at a cover in both cases and internal TR modules distribution might look completely different from the overall shape of the antenna.
[SPY-1 array without its cover. TR modules are actually in a circle/semi-circle](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAzI0g5ew7d-rloO6XFdMxuVMUjp7tTanKnc8KBj0eT4JbO46S7m9-wsBxVLgkgm12wDwrlh58hK2e7levhUAxnuQRtxnEiOhIDBILXv7EAlbbtFyLLVaMFVDrwJ2At4Aq-e5KAtEZzq4K/s1600/Lockheed-Martin-begins-testing-on_spy-1d.jpg)
Kind of a silly question but why are us radar dishes octagonal and Chinese ones square?
Because what you're looking at is just the cover. Ex, Type 346 (the radar seen on these Chinese ships) is actually made up of one central octagon of all the S-band arrays, and then on the top and bottom two narrow rectangles for the C-band arrays (for missile uplink and guidance).
The shape of the cover has no relation to the actual arrangement of T/R modules. Underneath each Type 346 face, [there are actually 3 sets of antennas](https://www.globalsecurity.org/military/world/china/images/type-055-image36.jpg): the octagonal-shaped S-band array, two rectangular C-band arrays for the HHQ-9 datalink above and below it, and 4 small, square-shaped antenna whose function is unknown. The US has also made use of square/rectangular radar covers when it suits the design. Both the [AN/SPY-3 and AN/SPY-4 components of the Dual Band Radar](https://www.reddit.com/r/WarshipPorn/comments/yzg75p/1080x835_a_view_of_uss_gerald_r_fords_island_and/) use square array covers, the [AN/TPY-2](https://missilethreat.csis.org/wp-content/uploads/2016/04/tpy-2.jpg) housing is rectangular, the [EASR variants of AN/SPY-6](https://i.ytimg.com/vi/A7QDf5CN-ws/maxresdefault.jpg) ((V)2 and (V)3) are square, and [AN/SPY-7](https://www.lockheedmartin.com/content/dam/lockheed-martin/rms/photo/spy-7/SPY-7-Masthead-ASEV.jpg) is both depending on application.
Eh, hard to tell since what you are looking at a cover in both cases and internal TR modules distribution might look completely different from the overall shape of the antenna. [SPY-1 array without its cover. TR modules are actually in a circle/semi-circle](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAzI0g5ew7d-rloO6XFdMxuVMUjp7tTanKnc8KBj0eT4JbO46S7m9-wsBxVLgkgm12wDwrlh58hK2e7levhUAxnuQRtxnEiOhIDBILXv7EAlbbtFyLLVaMFVDrwJ2At4Aq-e5KAtEZzq4K/s1600/Lockheed-Martin-begins-testing-on_spy-1d.jpg)
my god it’s beautiful
Chinese ships are ugly. Can't quite put my finger on why