New-Tech Europe Magazine | Q3 2020

Figure 1: Sir J.C. Bose’s wireless millimeter wave (microwave) apparatus [1]

Figure 2: Sir J.C. Bose demonstrating his wireless millimetre wave (microwave) experiments at the Royal Institution, London in January 1897 [2]

Historical Background For as long as RF, microwave and millimeter wave systems have been developed and deployed, circuit designers have been faced with developing high-performance circuits that can withstand the rigors of their intended applications. Early discrete implementations evolved into increasingly more integrated solutions to reduce size and cost, as well as improving part to part uniformity. The methods of maintaining optimal operating conditions and protecting the circuitry against environmental hazards evolved in lock step. Electrical and mechanical requirements have never been mutually exclusive, though the engineering approaches to meeting their interrelated specifications have often been accomplished piecewise due to the limitations in analysis software, and sufficiently accurate simulation models. As operating frequencies increased, so too, did

concern. That is not to say the packaging was not important. Often, these systems were built into metal housings, and dealing with thermal management, mode suppression, and shielding was accomplished effectively, but done empirically, and with minimal regard to cost. It was all about getting the system to work. The volumes were low, so cost was less of an issue. Research and low-level production of broadband and mmW systems were more tolerant of this hands- on approach, and the balance of supply and demand was adequately met. Fast forward to the era of commercialized telecommunications, and the situation is far different. mmW bands, once the domain of research and niche applications, have become mainstream. 5G and massive MIMO 2 promise to accelerate the demand for mmW systems, with as much as 45% of the predicted 24GB of individual monthly data consumption to be delivered by

the difficulty of meeting these combined requirements. Operating at mmW bands is hardly a new concept. J.C. Bose presented his research on mmW to the Royal Institution in London in 1897 [2] [3][4], where he showed operation and measurements as high as 60 GHz (Figures 1. and 2.). Similar, independent workwas demonstrated by Lebedew in Moscow, also up to 60 GHz [5]. mmW applications and frequency allocations have existed for some time for uses including navigation, radiolocation, Industrial, Scientific and Medical research, space exploration, point-to-point communications and commercial telecommunications backhaul. In the early days of these applications, packaging the systems and supporting components was typically focused on physical protection, as they were often contained within fixed, environmentally-controlled enclosures. Protecting the individual active components was of less

1 Multiphysics is an approach where coupled processes or systems involving more than one simultaneously occurring physical field are used in an analysis. In this case it is an interdisciplinary analysis using the Finite Element Method (FEM), and Method of Moments (MoM). 2 Multiphysics is an approach where coupled processes or systems involving more than one simultaneously occurring physical field are used in an analysis. In this case it is an interdisciplinary analysis using the Finite Element Method (FEM), and Method of Moments (MoM).

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