можно купить готовый
https://russian.alibaba.com/product-detail/high-quality-manual-pig-sheep-electric-stunner-for-sale-60386327003.html?spm=a2700.8699010.normalList.28.14012e26aVKG8V
Что-то типа такой?
800/900/1800/1900/2100MHz
Omni Directional 1/2 Wave
Miniature 42 x 42 x 1mm
VSWR <3.0
RG178 Coax 50Ω Impedance
2-3dBi Gain (nominal)
Vertical Polarization
Admitted Radiation Power 1W