Where Can I buy these 3 antennas ?
https://www.tele.soumu.go.jp/giteki/SearchServlet2?PageID=jt01&ATF=185314002
In Japan, we must use authorized antennas.
You can take a look at the products listed in the following link to see if they meet your requirements.
I wonder where I can buy spring antenna, patch antenna and colinear antenna.