The project will develop and demonstrate a novel signal-transmissive-wall to solve an emerging challenge of wireless cellular connectivity in our current low and future zero energy buildings. The increasingly strict regulations of energy use in buildings call for air-tight and energy efficient envelopes which reflect the signals from cellular base stations and cause poor indoor cellular coverage. The signal-transmissive-wall has distributed embedded antennas on both sides connected through appropriate microwave circuits. It is passive in the best case and covers all frequency bands used in legacy and forthcoming cellular systems. Cost and future maintenance are reduced compared to active electronic solutions such as installing indoor cellular wireless infrastructure. We design the signaltransmissive-wall through multi-physics analysis covering electromagnetic, thermodynamic, mechanical and acoustic aspects.