This work presents the design of a compact microstrip filtenna for miniaturized Internet of Things (IoT) devices operating in the Long-Term Evolution (LTE) band. The proposed filtenna integrates a 3rd-order hairpin band-pass filter with a coplanar patch antenna on an FR4 substrate (εr = 4.4, thickness = 0.8 mm), enabling both radiation and interference suppression in a single structure. The filter provides a passband from 2.53 GHz to 2.68 GHz, matching the LTE band with low insertion loss and high transmission. The antenna section achieves good impedance matching and stable radiation performance. Simulation results show a resonant frequency around 2.6 GHz with a return loss better than −27 dB and an omnidirectional radiation pattern suitable for IoT applications. The proposed filtenna offers compact size, reduced circuit complexity, and improved out-of-band interference rejection for reliable LTE-based IoT communication.