Carriers suitable for transporting a plurality of articles through a microwave heating zone are provided. Carriers as described herein may include an outer frame and upper and lower support structures vertically spaced from one another to provide a cargo volume into which the articles are loaded. At least a portion of the upper and/or lower support structures may be formed of an electrically conductive material. Additionally, the carrier may include removable article spacing members, such as vertical spacing members and dividers, that can be selectively inserted to adjust the size and/or shaper of the cargo volume. Carriers as described herein may be configured to receive a variety of different articles, including trays and pouches, and the articles may be loaded into the carrier in a nested or overlapping manner.