Application Note for Tuneable PCB Antenna (850/1900MHz)
DIY PCB Antennas - One for IoT
pcb design - Ground plane for a GSM spring antenna with 4 layer PCB - Electrical Engineering Stack Exchange
How to Build a Cheap Yagi for 2450 MHz - TurboFuture
Advances in Antenna Technology for Wireless Handheld Devices
800/900/1800/1900 MHz GSM Antenna Cellular&WiFi Communication :Elecrow bazaar, Make your making Electronic modules projects easy.
Amazon.com: Lintratek 70dB Cell Phone Signal Booster for House CDMA 850MHz PCS 1900MHz Dual Band Mobile Signal Amplifier Repeater Directional Antenna - Boost 3G 4G Voice & Data : Cell Phones &