Miniaturized dual band antenna for LoRa wearable devices

A miniaturized dual-band antenna suitable for LoRa wearable devices is proposed. The antenna is composed of a substrate with a radius of 18 mm and above the 6 mm high ring bracket. A clockwise surround monopole and coupling branches are adopted to generate two low-frequency resonant modes on a certain miniaturized structure, which can meet the LoRa antenna performance requirements. The antenna achieves -10 dB impedance bandwidth of 476-502 MHz and 854-879 MHz, and can cover most of the working frequency bands of LoRa devices at 470-510 MHz and 863-868 MHz. The measured efficiency at the two operating frequency points of 490 MHz and 865 MHz is 15.56% and 27.91% respectively. The antenna has a simple structure, a wide coverage frequency, a small volume, and a good radiation performance in the working frequency bands, and has a certain engineering application value.