Nona‐band, hybrid antenna for metal‐rimmed smartphone applications

Abstract

A new, hybrid, nona‐band antenna of the size 80 × 8 × 5 mm3 is proposed for recent metal‐rimmed smartphone applications. The proposed design is composed of a metallic frame (external antenna) and an internal radiating structure. The proposed antenna is attached to the top part of the smartphone. It uses a microstrip feed as a direct coupling line for the internal radiating structure. The feed also represents a capacitive coupling feed for the overall metal‐rim antenna structure. The metal rim with a small gap of 2 mm is connected to the system printed circuit board by two grounding points. The proposed antenna excites four coupled loop modes, three slot monopole modes, three dipole modes, and one monopole mode. By incorporating the excited modes, the proposed antenna covers all recent smartphone applications in the frequency range between 0.79 and 6.0 GHz. The proposed design is described with great details and both simulated and measured results are used to establish its validity. The antenna performance with mobile phone components is also investigated. The results demonstrate that the proposed antenna represents an excellent candidate for applications such as GSM850, GSM900, GSM1800, GSM1900, UMTS2100, LTE2300, LTE2500, LTE3500, and WiFi5500 bands.

A Reconfigurable Metal Rim Antenna With Smallest Clearance for Smartphone Applications

“…But this design retained a large ground clearance of 15 mm between the system ground plane and the metal frame. In contrast, the designs in [8], [9], [10], [11], [12], [13], [14], [15], [16], [17],…”

“…Inductive coupling, called magnetic excitation in this paper, is always placed at the maximum current position (maximum magnetic field position); electric-magnetic excitation is placed between the maximum and minimum current position; The feeding method mentioned in Section II-B is a magnetic excitation, which can directly feed the metal rim without any matching circuit [2], [3], [6], [17]. When the electric or electricmagnetic feeding method is utilized for metal rim antenna design, an L-shaped feeding line as the excitation is always used to excite the metal rim mode [5], [7], [10], [13], [15], [18]. And it can also be replaced by a capacitor in series with the feeding line, which was used in this paper.…”

“…To obtain a good bandwidth and efficiency, one common method is to transform the metal rim into an antenna radiator. The metal frame can be divided into two categories: one is the entire metal rim as the antenna radiator [2], [3], [4], [5], [6], [7], and the other is a part of the metal rim as the antenna radiator [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18]. In [2], the whole metal frame was used as a radiator without any other antenna elements, and an inductive coupling feeding source was employed to cover the lower band from 0.8 GHz to 1.0 GHz and the middle band from 1.7 GHz to 2.7 GHz, respectively.…”

“…and [18] have utilized other techniques to design smartphone antennas, such as loading lump elements [8], [9], [10], [14], parasitic branches [10], [11], [15], [17], or distributed element matching networks [12], [13], [16] into the clearance area to obtain multi-band or wide broadband operation. In [9], an L-shaped microstrip line was used as a capacitive coupling feeding source to cover the lower band with a ground clearance of 5 mm, while an L-shaped grounded branch was employed to increase the bandwidth of the higher band.…”

“…In [9], an L-shaped microstrip line was used as a capacitive coupling feeding source to cover the lower band with a ground clearance of 5 mm, while an L-shaped grounded branch was employed to increase the bandwidth of the higher band. In [12], [13], and [16], the proposed antennas can cover the lower band (0.76-0.96 GHz) and middle band (1.7-2.7 GHz) without any matching work. However, these methods need a large clearance.…”