A mm wave circuit includes a multiplexer plate having first and second faces, and an output port in the first face. The mm wave circuit also includes a receiver having a receiver input port, the receiver being arranged on the first face and electrically earthed thereto, and an electrically insulating layer covering at least a portion of the first face, the electrically insulating layer having a top face spaced apart from the first face. The electrically insulating layer includes a via extending from the top face to the output port, the via having a via mouth arranged in the top face. The mm wave circuit also includes a receiving antenna at least partly covering the via mouth, the receiving antenna being connected to the receiver input port by a receive line.