An apparatus for performing a microwave ablation procedure is provided. The apparatus includes a catheter including an open proximal end and a closed distal end configured to percutaneously access tissue. A directional microwave antenna probe adapted to connect to a source of microwave energy selectively couples to the catheter. The directional microwave antenna is rotatable within the catheter for directing the emission of microwave energy therefrom to tissue

A microwave ablation system includes an energy source adapted to generate microwave energy and a power splitting device having an input adapted to connect to the energy source and a plurality of outputs. The plurality of outputs are configured to be coupled to a corresponding plurality of energy delivery devices. The power splitting device is configured to selectively divide energy provided from the energy source between the plurality of energy devices.

Microwave antennas and devices incorporating such antennas usable for performing procedures on or within a patient's body using a shaped microwave field.

Devices and methods for treating tissue with microwave energy used in applications such as destroying a soft tissue by microwave ablation and/or creating point, line, area or volumetric lesions. Various embodiments of flexible, low-profile devices are also disclosed where such device can be inserted non-invasively or minimally invasively near or into the target tissue such as cardiac tissue. The devices disclosed herein comprise antennas wherein the field profile generated by an antenna is tailored and optimized for a particular clinical application. The antennas use unique properties of microwaves such as interaction of a microwave field with one or more conductive or non-conductive shaping elements to shape or redistribute the microwave field.