An annular heat exchanger for a gas turbine engine is provided. The annular heat exchanger can include a first annular ring comprising a first main tube defined by a plurality of transduct segments; a second annular ring comprising a second main tube defined by a plurality of transduct segments and a curvilinear plate defining at least one channel therein that is in fluid communication with a transduct segment of the first main tube and a transduct segment of the second main tube.