An improved microchamber for electrical detection of biological cells was designed, fabricated and tested. The microchamber was formed between a gold coplanar stripline fabricated on a sapphire microscope slide and a single microfluidic channel fabricated in a polydimethylsiloxane cover. Compared with the previous design of a coplanar waveguide on a quartz slide with multiple microfluidic channels, the present microchamber was more sensitive, compact, rugged, and transparent. Tests on Jurkat cells in both time and frequency domains demonstrated single-cell sensing potential, as well as discrimination of live vs. dead cells. The test results could be explained by a simple equivalent-circuit model, which efficiently de-embedded the intrinsic cell properties from solution and electrode effects.