Leakage Reduction by Improved Radio Mounting Design: A product development project focused on reducing RF and water leakage in outdoor radio units

Abstract

Microwave hops is a technology used to transmit data wirelessly between two separate points in a telecommunications network. The data is transmitted and received with antennas connected to one or multiple radio units. Water and RF-leakage are two factors that are known to negatively affect performance. The project has been executed at the request of Ericsson AB and it has had two main focuses. Improving the existing interface between radio unit and antenna with regards to said types of leakage, and investigating and suggesting testing methods that enable objective testing of water leakage, interface force, and interface contact coverage. The attachment points, which connect the radio to the antenna, and their placement have been analyzed both with regards to rigid body misalignment and contact pressure distribution. The analysis showed that the current attachment point placement can cause low pressures on the side of the interface and that a symmetrical attachment point placement is preferable. A concept generation of alternative mounting mechanisms was performed with the results from the analyses as a base. The generated concepts were evaluated based on cost, assemblability and overall design. The final concept was further developed and a prototype was built to enable comparison with the current design with regards to interface pressure distribution. Pressure sensitive microcapsule films were used to test the concept. The prototype generated a more even pressure distribution compared to the current design with the chosen test method. However, the results indicated that the pressure limit of the film was exceeded, making conclusions regarding prototype performance hard to make. A literature study of commercially available testing methods was performed. Data of the investigated methods was gathered and compared in order to assess the methods applicability. Mass flow sensing was identified as a suitable method for testing water leakage, and three setups of different testing methods for force and contact coverage testing were compiled.