A novel design concept to reduce the frequency ratio of a dual-band dual-circularly polarized (CP) microstrip patch antenna (MPA) is presented by using its reshaped TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> , TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> , and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> modes. First, the far-zone radiated fields of the traditional MPA are theoretically investigated. It demonstrates that the normal |E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</sub> | and |E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">φ</sub> | fields at xoz plane are orthogonally generated under its TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> modes, respectively. Unfortunately, its TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> mode radiates the nonbroadside |Eθ| fields at xoz plane. Then, an open-ended stub is loaded around the edge of the radiator, aiming to reshape the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> mode as the broadside radiation. After that, the patch width is decreased with the loading of two shorting pins. The main target is to move the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode resonating between TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> modes. Finally, the proposed antenna is fabricated and tested. The results illustrate that its left-hand CP and right-hand CP radiation patterns are satisfactorily acquired at around 2.134 and 2.223 GHz, respectively, thus gaining a small frequency ratio of around 1.04. Meanwhile, the antenna holds the low-profile (0.02 free-space wavelength), small-backlobe, single-layer, singlefed, and single-radiator properties.