Characterization of Effects of Door Materials to Integrated Radio Radiation Patterns in Locker Unit

The current trend of delivering goods is to use lockers located close to the customers. The locker needs to communicate with a delivery system, which is most convenient to achieve with wireless technologies. There are mechanical, industrial design and reliability advantages to place a radio unit inside of the locker. However, it is challenging from a radio communication perspective, especially with conducting door material like metal. In this work, RF radiation performance from inside of the metallic locker with two different door materials was studied. The studied RF frequencies cover operational frequencies of LTE NBIoT, Sigfox, LoRa, Wifi, and 5G NR at 3.5 GHz. The simulations and measurements show that the radiation pattern of the metal door locker resemble radiation pattern of array. The main radiation direction with metal doors can be backside of the locker, while with a wood laminate the primary radiation direction is toward front side of the locker.