A system for performing multi-tool minimally invasive medical procedures through a single instrument port into a body cavity includes an expandable frame that carries a pair of tool cannulas, each of which has a lumen for receiving a tool useable to perform a procedure in the body cavity. Alkanoates having from 2 to 6 carbon atoms are preferred, with acetates most preferred. A closed-ended dielectric transmission path is formed in the multilayer dielectric substrate in the layer direction, with a length of about \u03bbg4, where \u03bbg is an in-substrate effective wavelength of the signal wave.