Keywords

These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

1 Introduction

Recently, along with rapid advancement of wireless technology wideband compact antenna for lower frequency bands become a challenging issues to the antenna researchers. Microstrip feed printed antennas has become most studied structure due to its some interesting features, like low cost, compact, lightweight, easy fabrication and installation.

Many low-cost small antennas have been investigated over the last decade [1, 2]. However, the appeal of wideband antenna is becoming robust as today mobile wireless devices are needed to have the function of multi-standard operations. Li et al. proposed a broadband planar antenna which achieved 40 % impedance bandwidth (VSWR < 2) with antenna size of 18 × 69 mm2 [3]. Alam et al. proposed parasitic element loaded antenna for mobile wireless antenna which can cover GSM 1800, GSM 1900, GSM 2100, UMTS, Bluetooth (2.40–2.80 GHz), WLAN (2.40–2.485 GHz), WiMAX (2.50–2.69 GHz), and WiMAX (3.40–3.60 GHz). However, the antenna dimension was 50 × 62.9 mm2 [4]. Montero et al. proposed a coplanar hybrid antenna having size of 56 × 24 × 6 mm3 for GSM 1800, PCS 1900, UMTS 2100, WLAN 2450/5200 applications [5]. Spline-shaped ultra wideband antenna for mobile application is presented in [6], which can operate at DCS 1800, the PCS 1900, the UMTS (1920–2170 MHz), and the ISM (2400–2485 MHz) bands. Though, the antenna was 51.2 × 60 mm2. Dual arm structure antenna is illustrated for DCS, PCS, UMTS and WLAN application in [7] with physical size of 119 × 50 mm2.

In this communication, a new broadband triangle shape antenna is illustrated for handheld devices, which can operate at GSM 1800, GSM 1900, GSM 2100, UMTS, Bluetooth (2.40–2.80 GHz), WLAN (2.40–2.485 GHz), WiMAX (2.50–2.69 GHz), and WiMAX (3.40–3.60 GHz). The physical dimension of the presented antenna is 37 × 47 × 1.6 mm3, which is compact than reported antennas. The antenna performances has been analyzed and experimentally validated. Additionally, the electromagnetic absorption rate of the proposed antenna has been investigated.

2 Antenna Design

The geometric layout of the suggested antenna is depicted in Fig. 1, which is printed on low cost FR4 substrate material of 37 × 47 × 1.6 mm3. The proposed antenna assimilated with inverted C-shaped ground plane and a triangular shape radiator. A 50 Ω microstrip feeding line is connected with prime radiator. The presented antenna parameters are: L = 47 mm, W = 37 mm, Wf = 1 mm, Lf = 20 mm, L1 = 22 mm, L2 = 15.55 mm, L3 = 15.55 mm, L4 = 25.75 mm, L5 = 24.5 mm, L6 = 12 mm, L7 = 15.5 mm and h = 1.6 mm.

Fig. 1
figure 1

Geometric layout of the presented antenna. a Top view, b bottom view, c side view

Full size image

3 Result and Discussions

The proposed antenna prototype has been fabricated and experimentally validate with measured one. The design and simulation of the proposed antenna have been performed by using the commercially available CST microwave studio and Ansoft high-frequency structure simulator (HFSS) software. The VSWR measurement has been performed using an Agilent TE8362C network analyzer. The surface current distribution of the presented antenna is presented in Fig. 2. It is shown from Fig. 2 that the maximum current flows in feed line towards triangle shape radiator. There are some leakage current near feeding port.

Fig. 2
figure 2

Surface Current distribution of the presented antenna a At 1.8 GHz b At 2.4 GHz  c At 3.6 GHz

Full size image

Moreover, the smith chart of the presented antenna is also illustrated in Fig. 3. The simulated and measured VSWR is presented in Fig. 4. It is seen that the antenna has achieved measured VSWR ≤ 2 impedance bandwidth of 1.05 GHz (1.66−2.71 GHz) and 1.42 GHz (3.28−4.7 GHz), which cover GSM 1800, 1900, 2100, UMTS, Bluetooth (2.40–2.80 GHz), WLAN (2.40–2.485 GHz), WiMAX (2.50–2.69 GHz), and WiMAX (3.40–3.60 GHz). From Fig. 4, it is observed that the measured and simulated VSWR are identical. The radiation pattern of the presented antenna has been demonstrated in Fig. 5. It is shown from Fig. 5 that the antenna shows nearly omnidirectional radiation pattern at E-plane. Moreover, the researchers have been analyzed specific absorption rate [8–10]. To comply with the requirement of IEEE and ICNIRP guideline, the SAR value of the presented antenna has been analyzed and presented in Fig. 6. It is observed from Fig. 6 that, the electromagnetic absorption rate fulfill the requirements of IEEE and ICNIRP guideline for the electromagnetic absorption rate.

Fig. 3
figure 3

Smith chart of the presented antenna

Full size image
Fig. 4
figure 4

Measured and simulated VSWR of the presented antenna

Full size image
Fig. 5
figure 5

Radiation pattern of the presented antenna at a 1.8 GHz and b 2.4 GHz

Full size image
Fig. 6
figure 6

a 10 g SAR at 1.8 GHz, b 10 g SAR at 2.4 GHz

Full size image

4 Conclusion

A new compact triangle shape radiator with inverted C-shape ground plane is presented for mobile wireless communication. Experimental result shows that the obtained VSWR ≤ 2 impedance bandwidth of 1.05 GHz (1.66−2.71 GHz) and 1.42 GHz (3.28−4.7 GHz) with compact size of 37 × 47 × 1.6 mm3. So, the proposed antenna can play significant role in mobile wireless communication.