A standing wave oscillator includes a cross-coupled differential transistor pair having a pair of input terminals and a pair of output terminals; and a resonant circuit coupled to the input terminals of the cross-coupled differential transistor pair. The resonant circuit includes: a capacitance between the input terminals of the cross-coupled differential transistor pair; and a differential dual-mode coplanar waveguide (CPW) having opposite differential ends thereof connected to respective input terminals of the cross-coupled differential transistor pair. CPW ground lines of the differential dual-mode coplanar waveguide each have a first end thereof connected to the first supply voltage and have a second end thereof floating or unterminated.