Fourier transforming microwave impulses using low-cost analog circuits

In this paper, a low-cost analog circuit architecture to acquire the (complex-valued) spectrum of microwave impulses is designed. The proposed architecture consists of multiple channels to down-convert the input signal, each of which obtains a small portion of the input´s spectrum. Overlapping bands are designated in between every two adjacent channels, so that multiple narrow-band outcomes can be accurately merged to construct the entire wide-band spectrum through post-processing. Our circuit is tested by input impulses with spectrum centered at 2.1 GHz. The input signal´s spectrum (including both magnitude and phase) obtained by our circuit shows excellent agreement with the data measured by a 40-GHz oscilloscope.