Multiband monopole antenna with minimised ground plane influence for portable devices

Abstract

A multiband monopole antenna with minimised ground plane influence for portable devices is presented. This antenna operates at LTE band 13 (0.746–0.787 GHz), GPS, LTE band 11 (1.427–1.495 GHz), LTE band 3 (1.71–1.88 GHz), WLAN (2.4–2.48 GHz) and WiMAX (3.3–3.88 GHz) with at least −6 dB of reflection coefficient. The performance of antennas for portable devices is commonly influenced by the ground plane to result in variation in terms of operating frequency, impedance bandwidth and radiation pattern. Via a parametric investigation of the antenna geometry and its integration with peripherals devices, it is validated that the influence of the ground plane is minimised by adjusting the feed position. This in turn reduces the current distribution on the ground plane. It is also noticed that the impedance matching level is also more robust with the reduction of ground plane influence. The antenna features an omnidirectional radiation pattern across the all operating frequencies. Fabrication and assessment of the fabricated antenna indicated a close agreement with simulations.

Multiband triple folding monopole antenna for wireless applications in the laptop computers

“…Many promising antennas with multiband characteristics for wireless operations have been reported in the past decade 1–19 . In Fei et al, 1 a dualband printed compound loop antenna consisted of a small inner rectangular ring, an outer rectangular loop and a parasitic strip to operate in 2.4/5 GHz of WLAN and 3.5 GHz of WiMAX bands have been studied.…”

Multiband , miniaturized, maze shaped antenna with an air‐gap for wireless applications

“…From Table 5, it can be observed that the proposed antenna has the following features: Unlike to all existing state of arts, 1‐24 the proposed antenna is simple in design, compact and has dimensions of only 6 × 4 mm 2 , thus it can reduce the space required for mounting the antenna inside an actual laptop computers. Unlike those reported in References 16, 18, 19, the proposed antenna can operate within the desired bands of interest without using any additional lumped elements (inductors, capacitors etc. ), 3‐D structures and added holes or vias. Compared with References 1–5, 8, 9, 16, 18–20 the proposed antenna is suitable for different sizes of laptops and other portable devices. Unlike References 8, 9, 18, and the proposed antenna has exhibited broader fractional impedance bandwidths of 6.5% and 16% across the two operating bands. Compared with those in References 1, 4, 5, 11, 14, 21, 23, and the gain of the proposed antenna is above 3 dBi across all the operating bands. The proposed antenna can cover both the fundamental 2.4 and 5 GHz bands, unlike References 1–3, 7, 12. The proposed antenna does not require additional ground plane for affixing the antenna to system ground, unlike Reference 11 Unlike References 4, 5, 13, and the proposed antenna does not use expensive substrate. …”

“…From the available open-literature, extensive research work has been carried out on antenna miniaturization in terms of novel structures and antenna performances. To accommodate the demand for rapid development in wireless laptop applications, 1 proposed a monopole antenna comprising of spiral loop strips, stub, and ground plane. However, the overall size of the spiral main radiating element is 18.6 × 20 mm, and thus it is unattractive for modern portable thin laptops.…”

“…This poses a good challenge to antenna designers in terms of design, fabrication, and reliability with respect to size, mounting, and cost. From the available open‐literature, extensive research work has been carried out on antenna miniaturization in terms of novel structures and antenna performances 1‐24 …”

A novel, very low profile, dual band inverted ‘E’ monopole antenna for wireless applications in the laptop computer

“…The Industrial Scientific Medical (ISM) bands, namely 2.4 GHz (2.40-2.48) GHz and 5 GHz (5.15-5.85) GHz are used in the WLAN/WiMAX environment. Therefore, multiband antennas including inverted-F [1,2], the coupled-fed planar inverted-F antennas in [3,4], branched monopole antenna [5], dual band monopole antenna [6], printed antenna [7], monopole antennas using reactive components [8,9], antennas using additional ground plane [10,11], meander antennas [12,13], folded antennas [14,15], uniplanar antennas in [16,17,18,19], broadband antenna [20], antennas having thickness of 1 mm [21,22,23,24] and cloverleaf-shaped monopole antenna [25] have been reported recently for WLAN/WiMAX technologies for the laptop computers. From the above mentioned antennas, it is understood that miniaturized and ultra-thin antennas showing high performance with less complex structure and covering WLAN/WiMAX bands for laptop applications are posing challenges for antenna designers due to shrinking of height and thickness of outside frame of the laptop display.…”