Abstract: A radio frequency (RF) coaxial transmission line to be positioned within a wellbore in a subterranean formation may include a series of coaxial sections coupled together in end-to-end relation. Each coaxial section may include an inner conductor, a dual-wall outer conductor surrounding the inner conductor, and a dielectric therebetween. Each of the dual-wall outer conductors may include an outer wall and an inner wall spaced apart therefrom defining a fluid passageway. Each coaxial section may further include a threaded endpiece coupled to each opposing end of the dual-wall outer conductor and having threads to define an overlapping mechanical threaded joint and an electrical joint with an adjacent threaded endpiece.

Abstract: A rigid radio frequency (RF) coaxial transmission line to be positioned within a wellbore in a subterranean formation may include a series of rigid coaxial sections coupled together in end-to-end relation. Each rigid coaxial section may include an inner conductor, a rigid outer conductor surrounding the inner conductor, and a dielectric therebetween. Each of the rigid outer conductors may include a rigid outer layer having opposing threaded ends defining overlapping mechanical threaded joints with adjacent rigid outer layers. Each of the rigid outer conductors may also include an electrically conductive inner layer coupled to the rigid outer layer and having opposing ends defining electrical joints with adjacent electrically conductive inner layers.

Abstract: An antenna assembly may be positioned within a wellbore in a subterranean formation. The antenna assembly includes a tubular antenna element to be positioned within the wellbore, and an RF coaxial transmission line to be positioned within the tubular antenna element. The RF coaxial transmission line includes a series of coaxial sections coupled together in end-to-end relation, each coaxial section including an inner conductor, an outer conductor surrounding the inner conductor, and a dielectric therebetween. Each of the outer conductors has opposing threaded ends defining overlapping mechanical threaded joints with adjacent outer conductors.

Abstract: A radio frequency (RF) applicator may be rotated during positioning within a wellbore in a subterranean formation. The wellbore may have at least one bend therein. The RF applicator may include a series of tubular conductors, and a respective bendable tubular dielectric coupler rotationally interlocking opposing ends of adjacent ones of the series of tubular conductors to define a tubular antenna. The RF applicator may include at least one RF feed conductor extending within the tubular antenna and connected to the series of tubular conductors.