Compact omnidirectional dual‐band dipole antenna with reduced ground plane effect

Abstract

In this letter, a compact omnidirectional dual‐band antenna is designed for wireless local area network applications. The proposed antenna is printed on the two sides of an FR4 substrate that the total dimension is 12 × 46 × 0.5 mm3. A dipole antenna is used to cover the lower operating band (2.45 GHz), while a capacitances‐loaded patch generates a higher resonance (5.5 GHz). This antenna has a good impedance matching in the operation band, and the gain is 2.28 and 4.42 dBi in the lower and upper bands, respectively. To address the problem that the performance will drastically decline when the antenna is located on a ground, a quarter wavelength spiral line is employed to decrease the negative effect of the ground. Two proposed dipole antennas, placed on a horizontal ground as a MIMO antenna system, are analyzed with different configurations. The results reveal that the proposed method can effectively reduce the ground plane effect and improve the diversity performance, which has huge potential applications in MIMO system.

Analysis and Design of a High Gain Multiband Antenna Based on Metamaterials for RFID Applications

“…The antenna presented in this paper has a higher gain in certain frequency bands, especially in the UHF band, reaching up to 7 dB, which emphasizes the superiority of our design in this aspect. Moreover, the antennas in references [10,14,26] operate on two bands and have miniaturized size but are inadequate compared to our proposed design. This comparison shows that our antenna can cover more bands than the other designs.…”

“…However, this can lead to a deterioration in the performance of the antenna in terms of gain and directivity. Another technique [6][7][8][9][10] has been proposed to obtain a multiband antenna with smaller size, namely, to change the shape of the antenna, which can drastically reduce the amplitude of the current distribution in the radiator near the ground to suppress unbalanced current. Although these antennas have the advantage of compact size, the gain of the antennas remains very low.…”

“…where the wave number K eff can be approximated by K eff = w/c ε eff μ eff , ε eff is the effective relative permittivity, w is the angular frequency, and K 0 is the free space wave number. Considering (3)-( 5), (10), and (11), the estimated values of circuit elements can be obtained and are indicated in Table 4.…”