In this paper, a novel double square slot antenna for 5G Small-Area Wireless Access Points (SAWAPs) at 3.6 GHz. The proposed antenna is specifically designed to enable 5G SA deployed in street furniture, such as street lampposts, utility poles or technical cabinets. Several design requirements have been particularly addressed, such as, reduced form factor (to be easily integrated in existing street furniture), operation in the 5G FR1 n78 frequency band with a bandwidth defined from 3.4 GHz to 3.8 GHz, while presenting an omnidirectional radiation pattern in the azimuth plane with at least 5dBi of gain. The proposed antenna layout is composed of two inset feed microstrip patches with both etched patch and ground plane, previously developed by the authors, disposed in the configuration of an array. An improved ground plane is employed to maximize the antenna bandwidth. The antenna optimisation is achieved with the aid of parametric simulations realised in CST MWS. After optimisation in CST MWS, the antenna designed in Rogers 4350B substrate, presents a final dimension of 130×55×1.6 mm 3 , a bandwidth of 400 MHz, defined from 3.4 to 3.8 GHz, with an omnidirectional radiation pattern with a realised gain higher than 5 dBi in the entire bandwidth. The impact of employing the developed antenna in a modern style street lamppost is also presented.