RF

Anti-shoplifting tags teardown

Thixotropy article tells about the technology of anti-shoplifting tags used on store merchandise. They are high-Q tank circuits which if carried between a transmitting and receiving panel at a store’s doorway, they enhance 9 MHz signal propagation between those two panels and the alarm goes off. When a purchase is made, the store clerk deactivates

Shields are your friend, except when…

Shields are your friend, except when… article tells that engineers just love to put shields on circuits, mostly as a defensive measure against signals on the outside getting into and disturbing our circuits, but they also keep signals inside from getting out and this really makes the folks responsible for EMI compliance happy. Even on

Wifi gesture control

Gesture control uses WiFi doppler shift article tells that researchers at University of Washington have built a WiFi-based gesture control system. The system uses doppler shift in Wifi signal combined with Software-Define Radio (SDR) to detect humans moving near the devices. The researchers see WiSee as a novel interaction interface that leverages ongoing wireless transmissions

Google spectrum database

Google Offers Sneak Peek at Your Available Spectrum article tells that Google.org is publicizing a Spectrum Database that monitors unused spectrum frequencies (a.k.a. white space) across the US. The aim is to allow industry stakeholders and the public to utilize unoccupied frequency ranges better through dynamic spectrum sharing. The database is undergoing a public trial

PCB material for RF

Is plain old FR-4 PCB material suitable for use in RF designs? Many say no, fewer say yes – who’s right? What PCB material do I need to use for RF? article tries to answer this question. It says that FR-4 can be suitable for many RF designs. This is not to say that FR-4

802.11ad at 60GHz Will Knock Your Socks Off?

Interop: Don’t sweat 802.11ac Wi-Fi – because 802.11ad will knock your socks off article tells that industry experts at Interop NY already look beyond the coming advent of 802.11ac. While the Wi-Fi world is rightly abuzz over the rapidly approaching large-scale deployment of the new 802.11ac standard, experts at an Interop NY panel said today

Ideas to boost your WiFi signal

Antenna on the Cheap (er, Chip) article shows how to build a simple “classic” WLAN antenna from Pringles potato chip can. I have built antenna based on this plan (some improvising) and I can say that it worked. Besides WLAN I have used it for wireless video at 2.4 GHz. Cantenna article tells that in

Human reaction to radiowaves

Humans seem to be more sensitive to be more sensitive to weak very high frequency field than what I have believed. According to research presented in academic dissertationSpontaneous movements of hands in gradients of weak VHF electromagnetic fields concludes that spontaneous hand movement reactions occurred as a response of the human body to the gradients