GHz ultrasonics with arbitrary code excitation

Recently we developed a high frequency coded signal ultrasound microscope based on quadrature modulation [1, 2]. The device allowed pulse-echo operation at 300 MHz, however, local oscillator crosstalk reduced the SNR of pulse compression. To achieve GHz-range operation we present an improved design with new RF-components. The new design improved SNR by 16 dB compared to [2]. We also investigated the use of a dual-band chirp to further reduce the local oscillator interference. We successfully tested the device with a GHz ultrasound transducer in 0.9-1.1 GHz band using an arbitrary TX code. This achievement is a first step towards bringing the advantages of coded excitation into GHz ultrasound microscopy.