Microwave and Millimeter-Wave High Frequency Circuit Material Performance (up to 110 GHz)

Description:    Technical Education Webinar Series

Sponsored by: Rogers Corp.

Abstract:
Understanding which circuit parameters affect the performance of millimeter wave circuitry is critical when selecting materials for designs operating up to W-Band (75 to 110 GHz). As a natural artifact of dielectric materials, the relative permittivity (er, dielectric constant, Dk) will slightly decrease with increasing frequency. Additionally the dissipation factor (tand) will increase with increasing frequency. The range of frequency for these general statements start below microwave frequencies, at about 10 MHz, and go up to low millimeter wave frequencies, about 110 GHz. The er vs. frequency and tand vs. frequency trends are typically due to dipole moment behavior within the material when the material is subjected to varying electric fields. 

There are other frequency dependencies of high frequency circuit materials, and one important topic is the copper surface roughness. Conductor surface roughness will impact conductor loss and phase propagation and this material property is frequency dependent. As a general statement, the surface roughness will have less impact on circuit performance at low microwave frequencies than higher frequencies. 

Insertion loss is a circuit performance issue and closely tied to high frequency material attributes. The components which make up insertion loss are frequency dependent. Understanding these different components can be difficult since there are interactions between circuit design and material properties, along with the frequency dependency. Additionally, supplement losses are contributed by circuit fabrication and applied finial plated finishes.

This webinar will discuss the following topics:
• Overview of frequency dependent dielectric behavior 
• Dissection of insertion loss contributions from frequency and material variables
• Copper surface roughness effect on insertion loss and phase propagation
• Measured data of insertion loss and phase reflecting the previous topics
• Comparing measured insertion loss of different circuit designs and plated finishes