In this paper, the millimeter-wave circuit miniaturization techniques using BCMLR and interdigital resonators are introduced. Using these structures, the physical size of the on-chip filter can be dramatically reduced. The designed BPFs are implemented in standard 0.13-μm SiGe and 0.1-μm GaAs technologies for concept approval. Compared with other state-of-the-art work at millimeter-wave frequencies, our proposed designs have the merits of ultra-compact size as small as 0.038 mm2, competitive insertion loss (1 dB in GaAs BPF) and harmonic suppression of more than 44 dB.