The RF spectrum grows increasingly crowded every year due to technological advancement and more accessibility to wireless devices. Overcrowding leads to the desire for frequency agile microwave systems with dynamic spectrum access. One way to achieve this agility is by changing the frequency band of operation with mode-reconfigurable devices. This thesis presents three unique Butterworth bandpass mode-reconfigurable filters, designed to be enabled with the use of non-toxic Galinstan liquid metal. Galinstan is used to fill or empty certain vias and channels which change SIW cavity boundaries and external excitation to achieve reversible and repeatable operation. There are three states available in the filters within the C-band of 4-8 GHz: dual band, low band, and high band operation. To achieve low band operation by turning off the high band, a transmission zero is generated and centered over the high band resonant frequency. To achieve high band operation by turning off the low band, the first mode is shifted up to overlap with the second mode resonant frequency. The simulated and measured results showed that either band could effectively be turned off to allow multiband access or switching between the individual bands. The reconfigurable filters offer a promising technique for dynamic frequency access in future wireless systems.