This paper analyses the impact of anodic bonding technique on the transmission loss in 23GHz pressure transducers. The transducers consist of a thin high resistivity silicon membrane and a 23GHz planar resonator placed inside a cavity. Two types of transmission line are used here for designing the resonators: probe-fed coplanar lines and aperture-coupled microstrip ones. Transducers based on aperture-coupled microstrip resonators and manufactured from the anodic bonding process for assembling the silicon membrane to the glass substrate are the most promising low-loss solution. It is actually shown that, at the resonant frequency of the planar resonator, the measured transmission loss in a probe-fed coplanar transducer is about 4dB when using bonding with the photoresist as an intermediate layer, while it is only of 2.55dB when applying the anodic bonding assembling process. However, we report for the first time that very high and unexpected transmission loss (>30dB) occurs when using anodic bonding technique to manufacture the 23GHz aperture-coupled microstrip transducers.