The technology to inhibit a mobile phone exists and, if one has the soul of a saboteur, it can be purchased on the Internet for a few tens of dollars in the market. A frequency jammer consists of a small device that emits an electromagnetic wave that cancels the frequency of the mobile phone in an area of tens of meters. Their use is usually restricted by law since they are used by state forces for protection work or by organized gangs of thieves in the theft of vehicles or houses.
There is also the possibility of acquiring the technology for the opposite. A frequency inhibitor detector allows detecting a burglary attempt when intruders want to disable an alarm in a home for example. It is a service that alarm companies market, reaching the contradiction that they sell it as an additional service to cover a vulnerability in their own protection systems.
The mobile phone jammer not only work for mobile telephony but can also cancel the WiFi signal, GPS, radio, road radars, etc. But not all electromagnetic signals are equally easy to inhibit. Communications that use several radio transmission channels at the same time are more robust to attacks.
The inhibition of electromagnetic signals is very close to listening or spying on communications, reaching its maximum expression with the so-called ECHELON network that brings together English-speaking countries in an immense global communications listening network. It was conceived in times of the cold war and continues to be used to fight terrorism and industrial espionage, causing suspicion in civil society for its lack of legality and transparency.