Glass for 5G applications

The present drive for higher bandwidth has moved the mobile carrier frequency range to >5 GHz and possibly to >20 GHz in the near future. This has fueled the rapid development of 5 G and mm-wave technologies. The increased bandwidths available in the mm-wave frequency range allow for applications that require high-data-rate communications, which is not possible at lower frequencies due to Shannon's Capacity Theorem. However, the mm-wave frequency also presents a challenge to device performance due to the limitation on material properties. Many incumbent materials, such as silicon, ceramic, and polymer based substrates, suffer from high dielectric loss, rough surface, or poor durability to process chemistry. Silicate glass, on the other hand, has been shown to exhibit low dielectric loss, smooth surface, and high resistance to process chemistry. In addition, modern manufacturing technology has enabled silicate glass to be made with large size and thin form factor, which provides a clear advantage to lowering the cost. While many attributes of glass may be already familiar to the general scientific community, dielectric properties in the mm-wave frequency range have not been extensively reviewed. In this report, we show that mm-wave dielectric property can be changed by glass composition and post-forming processes. We also show examples of mm-wave devices that can be made with glass.