Mobile phone jammer is an instrument used to prevent cellular phones from receiving signals from base stations. Cell phone jammers block cellular phones signal by sending out radio waves along with frequencies that cellular phones use. This will causes interference with the communication between cellular phones and towers.

Older jammers sometimes were limited to working on phones using only analog or older digital mobile phone standards. Newer models such as the double and triple band jammers can block all widely used systems. Every jamming device has an antenna to send the signal. Some are contained within an electrical cabinet. On stronger devices, antennas are external to provide long range and may be tuned for individual frequencies. Micro strip antenna is used for jammers.

Smaller jamming devices are battery operated. Some use cellphone batteries. Stronger devices can be plugged into a standard outlet or wired into a vehicle’s electrical system.