In the last years, the development of broadband microwave sensors for cell detection has become a great challenge. In this work, a broadband microchamber integrated with microfluidics is used for cell detection in the GHz range. Measurements of scattering parameters have been carried out, demonstrating the capability of the device to discriminate different number of cells between the electrodes. Stable and reliable results on Jurkat cell solutions have been achieved. An equivalent circuit model, dependent on the number of cells trapped within the channel, has been extracted from the experimental data sets. We demonstrate the possibility to detect and isolate the electrical contribution of biological cells.