Ting-Wei Kang

On-Board Printed Coupled-Fed Loop Antenna in Close Proximity to the Surrounding Ground Plane for Penta-Band WWAN Mobile Phone

A small-size coupled-fed loop antenna suitable to be printed on the system circuit board of the mobile phone for penta-band WWAN operation (824-960/1710-2170 MHz) is presented. The loop antenna requires only a small footprint of 15 x 25 mm2 on the circuit board, and it can also be in close proximity to the surrounding ground plane printed on the circuit board. That is, very small or no isolation distance is required between the antennas radiating portion and the nearby ground plane. This can lead to compact integration of the internal on-board printed antenna on the circuit board of the mobile phone, especially the slim mobile phone. The loop antenna also shows a simple structure; it is formed by a loop strip of about 87 mm with its end terminal short-circuited to the ground plane and its front section capacitively coupled to a feeding strip which is also an efficient radiator to contribute a resonant mode for the antennas upper band to cover the GSM1800/1900/UMTS bands (1710-2170 MHz). Through the coupling excitation, the antenna can also generate a 0.25-wavelength loop resonant mode to form the antennas lower band to cover the GSM850/900 bands (824-960 MHz). Details of the proposed antenna are presented. The SAR results for the antenna with the presence of the head and hand phantoms are also studied.

Coupled-Fed Shorted Monopole With a Radiating Feed Structure for Eight-Band LTE/WWAN Operation in the Laptop Computer

A coupled-fed shorted monopole with its feed structure as an effective radiator for eight-band LTE/WWAN (LTE700/GSM850/900/1800/ 1900/UMTS/LTE2300/2500) operation in the laptop computer is presented. The radiating feed structure capacitively excites the shorted monopole. The feed structure mainly comprises a long feeding strip and a loop feed therein. The loop feed is formed at the front section of the feeding strip and connected to a 50-Ω mini-cable to feed the antenna. Both the feeding strip and loop feed contribute wideband resonant modes to combine with those generated by the shorted monopole for the desired eight-band operation. The antenna size above the top shielding metal wall of the laptop display is 4 × 10 × 80 mm3 and is suitable to be embedded inside the casing of the laptop computer. The proposed antenna is fabricated and tested, and good radiation performances of the fabricated antenna are obtained.

Small-Size Loop Antenna With a Parasitic Shorted Strip Monopole for Internal WWAN Notebook Computer Antenna

A simple meandered loop antenna with a parasitic shorted strip monopole, both printed on a thin dielectric substrate and folded to occupy a small size of 50 × 10 × 4 mm3, for the internal penta-band WWAN notebook computer antenna is presented. The antenna can provide two wide operating bands to cover the GSM850/900 operation (824-960 MHz) and the GSM1800/1900/UMTS (1710-2170 MHz) operation. The lower band is formed by two resonant modes, one half-wavelength loop mode contributed by the meandered loop and one quarter- wavelength monopole mode contributed by the parasitic shorted strip. The upper band is mainly formed by two higher-order loop resonant modes, with their good impedance matching obtained owing to the parasitic shorted strip. Further, in order to decrease the effects of the display ground and keyboard ground of the notebook computer on the antenna performances, two linear slits are embedded in the keyboard ground near the two connection hinges between the two grounds. The two linear slits function as current traps and can effectively reduce the excited surface currents on the keyboard ground. This leads to decreasing size of the effective notebook computer ground plane seen by the antenna. Thus, degrading ground plane effect on the performances of the internal WWAN antenna can be greatly reduced.

Coupled-fed PIFA with a loop feed for 8-band internal LTE/WWAN laptop computer antenna

Owing to the LTE (long term evolution) which can provide much higher data rate than the existing GSM and UMTS mobile networks, the internal antenna that can cover LTE/WWAN operating bands is preferred for the modern mobile communication device. All the 8-band LTE/WWAN operating bands include: three LTE bands in the LTE700 (698~787 MHz), LTE2300 (2300~2400 MHz) and LTE2500 (2500~2690 MHz), four GSM bands in the GSM850 (824~894 MHz), GSM900 (880~960 MHz), GSM1800 (1710~1880 MHz) and GSM1900 (1850~1990 MHz), and one UMTS band (1920~2170 MHz). Although there are some small-size 5-band WWAN laptop computer antennas published [1]-[5], they generally cannot satisfy the 8-band LTE/WWAN operation. In this paper, we present a promising internal laptop computer antenna with an acceptable size of 80 × 10 × 4 mm3 for practical applications. The proposed antenna is a coupled-fed PIFA with a loop feed; it can generate two wide resonant modes in the lower and upper bands to cover the desired 8-band LTW/WWAN operation.

Isolation improvement of WLAN internal laptop computer antennas using dual-band strip resonator

A high-isolation two-antenna structure comprising two small-size uniplanar WLAN antennas and a dual-band strip resonator embedded in-between for laptop computer application is presented. The proposed design occupies a small planar size of 9 × 50 mm2 when mounted above the top edge of the large supporting metal frame of the laptop display. The two WLAN antennas are coupled-fed printed PIFAs capable of covering 2.4/5.2/5.8 GHz band operation, each occupying a size of 9 × 13 mm2 and both facing to each other back-to-back with a spacing of 24 mm (that is, the total length of the proposed two-antenna structure is 50 mm). The embedded strip resonator functions as a dual-band wavetrap over the 2.4 and 5.2/5.8 GHz bands to trap the antennas near-field radiation between the two antennas, which effectively reduces the mutual coupling between the two antennas. Good measured isolation (S21 ≪ −18 dB) over the 2.4/5.2/5.8 GHz bands is obtained, which is acceptable for practical laptop computer applications. The proposed design works for the large groundplane condition in the laptop computer, different from many of the reported two-antenna designs working for the relatively much smaller groundplane conditions such as in the mobile phones and PC cards.