Low-Profile Dual-Band Microstrip Patch Antenna With Shorting Pins

A single-layer low-profile dual-band patch antenna is proposed in this letter. A Π-shaped slot is engraved on the radiating patch, separating it into a main patch and a parasitic patch to achieve the dual-band characteristics. The purpose of loading five shorting pins between the two vertical slots on the main patch is to turn down the two frequencies, which can generate TM
₀₁
mode and TM
₁₁
mode. To improve the impedance matching in the lower band and broaden the dual-band bandwidth, four shorting pins are placed on the edge of the long side of the parasitic patch, which can excite the TM
₁₀
mode. The combination of the TM
₀₁
, TM
₁₁
, and TM
₁₀
modes achieves the 3.45–3.7 GHz and 4.7–5.33 GHz dual band. Manufacturing and measuring a prototype. The results of the measurements indicate that the antenna achieves a dual-band with reflection coefficient less than −6 dB, which are 3.5–3.75 GHz (250 MHz, 7.0%) and 4.73–5.41 GHz (680 MHz, 13.4%) with peak gains of 6.23 and 5.06 dB in the low and high bands, respectively. The average total efficiencies in the dual bands are 64.2% and 77.3%, respectively.