Small‐size coupled‐fed printed PIFA for internal eight‐band LTE/GSM/UMTS mobile phone antenna

Abstract

A coupled-fed printed PIFA (planar inverted-F antenna) with a small footprint (about 415 mm 2 ) for eight-band operation covering the LTE700/2300/2500, GSM850/900/1800/1900, and UMTS bands in the mobile phone is presented. The proposed PIFA uses only a single radiating strip of length 45 mm which is short-circuited to the system ground plane of the mobile phone through a long inductive shorting strip and is capacitively excited by a long coupling strip. The capacitive excitation leads to the generation of the k/8 resonant mode at about 850 MHz and the higher order resonant modes at about 1900 MHz for the printed PIFA. The inductive shorting strip contributes additional inductance to achieve enhanced impedance matching for the excited 850 MHz band to achieve a dual-resonant behavior, which results in a wide lower band to cover the LTE700/GSM850/900 operation. A higher order resonant mode at about 2650 MHz is also contributed by the long inductive shorting strip. This resonant mode incorporating the one at about 1900 MHz generated by using the coupling feed forms a wide upper band to cover the GSM1800/1900/ UMTS/LTE2300/2500 operation. Compact integration of the proposed antenna with a nearby loudspeaker is also promising. Details of the results are presented.

Design of a coupled line feed structure for the wideband characteristic of a mobile internal antenna

“…Recently, dipoles that are printed on single plane have received wide attention because of the advantages of easy fabrication and integration of active MMIC elements [1,2]. Most of the reported designs of wideband enhanced gain dipoles have either a double layer structure or a balun configuration [3]. Nowadays, embedded antennas on the circuit boards are required for small electronic gadgets.…”

A Coupled-Fed Reconfigurable Antenna for Internal Lte Mobile Phone Applications

“…In recent years, many planar monopole antennas [1][2][3], loop antennas [4,5] and parasitic antennas [6][7][8] have been used in mobile phone to improve the disadvantages of PIFA antenna. A monopole antenna with three stubs was designed in [3].…”

“…The dimension of the antenna is only 15 mm × 42 mm that can cover CDMA800/GSM850/GSM900/DCS/PCS/UMTS/ISM/LTE2300/LTE2500, but the dimension is a little big. A parasitic antenna was proposed in [8], and the antenna consisted of a feed monopole and a short stub, with a coupling aperture for matching adjustment, so the antenna achieved a wide band. Furthermore, the space left for antenna design is getting smaller and smaller, several scholars proposed using impedance matching circuit at feeding port to obtain broadband coverage [9][10][11][12].…”

“…In order to cover a lower band LTE band 20 (800 MHz), an RF switch at shorting point is used to switch low frequency to 791 MHz. So the proposed antenna can work at GSM850, 900; DCS1800; PCS1900; WCDMA bands 1, 2, 4, 5, 8; TD-SCDMA bands A, F; CDMA BC0, BC1 and LTE bands 1,3,5,7,8, 20, 38, 39, 40, 41. Also, the total size of the antenna is 15 mm × 30 mm × 0.8 mm, which is very suitable for 4G slim smart mobile phone applications.…”

Antenna Solutions for 4G Smartphones in Laser Direct Structuring Technology

“…Due to dielectric loading effect and losses, the casing makes it easier for the antenna to operate down to 700 MHz especially shifting its resonance to lower frequencies. In [12], [13], similar antenna topologies using dielectric casings were presented. Although they are called Planar-Inverted-F Antennas (with coupled feeds), the main strategy is the same as using a shorter driven strip which capacitively excites a longer parasitic strip connected to the ground plane of the PCB.…”