An electronic device according to certain embodiments includes a first circuit board, a second circuit board including a communication module, a first antenna module disposed to be separate from the communication module, a flexible cable including a first connector connected to the first circuit board, a second connector connected to the first antenna module, a first extension extending between the first connector and the second connector, and a first receptacle disposed in the first extension, and a first coaxial cable including a third connector connected to the communication module, a fourth connector connected to the first receptacle, and a second extension extending between the third connector and the fourth connector.