This paper presents an Antenna-Array-Integrated Module (AiM) with a low pass filter (LPF) in LTCC multilayered substrate with low loss, high attenuation and small size in 28 GHz band. A differential feeding method for each patch antenna is employed to improve symmetricity of directivity for beam forming. The insertion loss of the LPF is less than 0.5 dB and the spurious emission in 2nd harmonic band of Band-n257 was suppressed by over 20 dB thanks to putting the LPF in front of the antenna. The symmetricity of the directivity for beam forming was improved owing to the differential feeding.