Microwave antenna assemblies incorporating a high-strength antenna coupler are described herein. The microwave antenna has a radiating portion connected by a feedline to a power generating source, e.g., a generator. Proximal and distal radiating portions of the antenna assembly are separated by a microwave antenna coupler. In embodiments, the described antenna coupler includes a dielectric member and at least one discrete coupling member. The coupling member isolates coupling forces, such as tension and torque, from the dielectric member, which may prevent cracking and reduce the incidence of mechanical failure of the dielectric. The coupling member may be formed from high strength materials, such as stainless steel, allowing greater coupling forces to be achieved when compared to couplers using only dielectric materials. The coupling member may additionally include reinforcing members which extend into the dielectric member for increased strength.