Parallel coil paths for downhole antennas

A method of manufacturing a coil antenna, the method comprising:

• forming a continuous groove in an exterior surface of a cylindrical body;
• the continuous groove comprising:
• multiple circumferential portions recessed radially inwardly from the exterior surface of the body, with each circumferential portion having a first end and a second end, the entire length of the portions being between the first and second ends and disposed within a plane, with each plane being parallel to one or more adjacent planes;
• and
• multiple intermediate transition portions, with each of the intermediate transition portions recessed radially inwardly from the exterior surface of the body for an entire length of the intermediate transition portions from the first end of one circumferential portion to a second end of an adjacent circumferential portion;
• and
• installing a conductor in the continuous groove such that the continuous conductor transitions between adjacent circumferential portions of the continuous groove in the intermediate transition portions of the continuous groove, thereby forming the coil antenna.

A system for measuring parameters of an earthen formation surrounding a borehole, the system comprising:

• an antenna assembly positioned in a borehole on a conveyance, the antenna assembly comprising a coil antenna with a continuous conductor installed in a continuous groove on an exterior surface of a housing, the continuous groove comprising:
• first and second circumferential portions recessed radially inwardly from the exterior surface of the housing, each of the first and second circumferential portions having a first end and a second end and the entire length of the portions being between the first and second ends, with the first circumferential portion disposed within a first plane and the second circumferential portion disposed within a second plane, and the first and second planes being parallel to each other;
• an inlet transition portion coupled to the first end of the first circumferential portion;
• an intermediate transition portion coupled between the second end of the first circumferential portion and the first end of the second circumferential portion the intermediate transition portion recessed radially inwardly from the exterior surface of the housing for an entire length of the intermediate transition portions between the second end of the first circumferential portion and the first end of the second circumferential portion;
• and
• an outlet transition portion coupled to the second end of the second circumferential portion;
• and
• the continuous conductor installed in the continuous groove such that the continuous conductor transitions between the first and second circumferential portions of the continuous groove in the intermediate transition portions of the continuous groove.