MTTS 2020: How Does Glass-weave Affect Millimeter-wave PCB Performance

John Coonrod explains how glass-weave affects millimeter-wave PCB performance. Many laminates used in the high-frequency industry have a layer or multiple layers of glass fabric.  The glass fabric is used to give some mechanical integrity to the laminate, however, the pattern of the glass fabric can impact the RF performance of a circuit.   The glass fabric pattern, in relation to the pattern of a circuit based on the laminate, can cause wave propagation anomalies which are undesired and is called the glass weave effect.  Typically, this effect is not a concern at lower frequencies. However, at higher frequencies, such as millimeter-wave frequencies, the wavelength is much shorter and the propagating wave behavior is more sensitive to small anomalies within the laminate. This video gives more details of the glass weave effect and shows how to quantify the glass weave effect in certain laminates.