This video is the start of many based around the design of 5 Hz antennas for the Wi-Fi spectrum.
The collinear antenna is an omnidirectional antenna much like the rubber duck dipole antenna. The main advantage of collinear antenna is its simple structure and relatively small dimensions.
This design is made up of three parts. The first is a ½ wave of 25.86mm. Second is a ¾ wave of 38.79mm. And the third is just shorter than a ¾ wave of 35.79 to reduce the capacitance effect as this antenna has no ground plane.