No. RF/Microwave design is an area best served by someone with an engineering training. Design entails taking known information, doing specific experiments if sufficient data is unknown, then using available materials/processes to design something that will be produced. While a physics major touches some of those, it certainly does not concentrate on the whole list.
But there are areas of microwaves that may be very well suited to a physics graduate. There is more work being done on very high frequencies (above 100 GHz). That area is more "science" than "engineering" oriented, with a lot of fundamental research being done. Any sort of radio astronomy work involves complex equations, general astronomy knowledge, and use of highly sophisticated equipment. A fair amount of microwave imaging work involves a physics bent, expecially with optics overlap, over pure engineering of hardware. So, in other words stay away from jobs requiring "design", but seek out those involving multi-disciplines, one of which is microwaves.
Just my two cents worth.