TESTS EVALUATE THE INFLUENCE OF JUNCTIONS ON PIM

AS the growth of wireless communications systems continues, the need t o minimize interference between channels and systems operated in paral lel is taking on greater importance. A significant part of this interf erence is created by the mixing of multiple transmission frequencies i n components with nonlinear characteristics-resulting in unwanted sign als termed intermodulation (IM) products, Among the IM signals that mu st be minimized are passive-IM (PIM) products, which are generated by passive (or linear) components, such as high-frequency connectors. A t est setup has been developed to evaluate the difference between variou s surface-plating materials with respect to their PIM characteristics at a point of contact. Unlike previous PIM investigations,(1-4) this t est setup (Fig I) supports variation of the contact pressure (with the aid of a piezo-electric crystal) with suitable precision to enable re producible IM measurements with a defined force or strike range as a f unction of the contact pressure.