How to implement a rotatable monopole antenna

Hi, I have a question about implementing a rotatable monopole antenna. My basic idea is the quater-wavelength monopole fed by coaxial cable in a plastic box with PCB inside. My question is how to create a connection from the box to the antenna which can blend to right angle(90) and rotatable which make it to be normal to the ground? Are there any connector or hitch can do so?
Thanks in advance

The most reliable solution is to use a length of flexible coaxial cable.

Another solution is to have your entire system in the box and flexible wires to the outside world for power and data.

Somewhat more complex is to have three orthogonal antennas and ratio the power between them.