| dc.description.abstract | In this paper, a miniaturized design of a microstrip-fed slot antenna is presented. We reduce the slot antenna size using slow-wave structures and equivalent circuit models. In the first part, the antenna will be designed to resonate at 2.45 GHz in the ISM band. Next, we use the characteristic of slow-wave structure with a larger phase constant to achieve the purpose of miniaturizing the antenna. In order to achieve a smaller size, we design a load in a slot antenna based on the concept of LC circuits, which is formed with equivalent capacitance and inductance. In the end, a half-wavelength slot antenna with a dimension of 0.14λ0 x 0.04λ0 has been successfully designed. Then, using the surface equivalence theorem and the dual theorem, the monopole antenna can be evolved into a quarter-wavelength slot antenna. Moreover, the quarter-wavelength slot antenna size has been reduced to 0.061λ0 × 0.04λ0. Finally, we use the butler matrix and miniaturized slot antennas to make a beam forming 1x4 antenna array. Additionally, we discuss the antenna array that uses miniaturized slot antennas, which has a lower gain, but better isolation than traditional slot antenna arrays. The isolation between the antenna array which is composed of miniaturized slot antennas can achieve about -20 dB. In the second part, we design a slot antenna based on the miniaturized slot antenna in the ISM band and increase the operating frequency to 28 GHz mmWave. Due to limitations of the process on line width, the slot antenna after miniaturization measures 0.14λ0 x 0.09λ0. And we also make into a beam forming 1x4 antenna array. Finally, the mmWave antenna array achieves a gain of 8.7 dBi. | en_US |