A Radar is a system of its own.. the antenna on KLJ-7 is slotted planar array of Chinese design(which is based on Russian design... or similar to it.)... now If you somehow don't use the Chinese antenna which by all means is stupidity and buy an European antenna to be used on the Chinese radar you would pay extra and require the radar to be config. according to antenna or vice-versa for proper performance... since Western designer would rather die than handing over their antenna design in Chinese hands and Chinese would at the same time not allow their radar in the hands of any NATO country... It is not possible.
The only possibility here is either import the whole system from Europe or China... making a Hybrid won't work even If you get the antenna and rest of radar from different places.
Assembling a radar is different thing... all the parts come from China and its assembled in Pakistan.. including antenna.