Cheng-Tse Lee

Planar Monopole With a Coupling Feed and an Inductive Shorting Strip for LTE/GSM/UMTS Operation in the Mobile Phone

A planar monopole having a small size yet providing two wide bands for covering the eight-band LTE/GSM/UMTS operation in the mobile phone is presented. The small-size yet wideband operation is achieved by exciting the antennas wide radiating plate using a coupling feed and short-circuiting it to the system ground plane of the mobile phone through a long meandered strip as an inductive shorting strip. The coupling feed leads to a wide operating band to cover the frequency range of 1710-2690 MHz for the GSM1800/1900/UMTS/LTE2300/2500 operation. The inductive shorting strip results in the generation of a wide operating band to cover the frequency range of 698-960 MHz for the LTE700/GSM850/900 operation. The planar monopole can be directly printed on the no-ground portion of the system circuit board of the mobile phone and is promising to be integrated with a practical loudspeaker. The antennas radiating plate can also be folded into a thin structure (3 mm only) to occupy a small volume of 3 × 6 × 40 mm3 (0.72 cm3) for the eight-band LTE/GSM/UMTS operation; in this case, including the 8-mm feed gap, the antenna shows a low profile of 14 mm to the ground plane of the mobile phone. The proposed antenna, including its planar and folded structures, are suitable for slim mobile phone applications.

Uniplanar Printed Coupled-Fed PIFA With a Band-Notching Slit for WLAN/WiMAX Operation in the Laptop Computer

A small-size uniplanar printed antenna suitable for 2.4/5.2/5.8 GHz WLAN and 2.5/3.5/5.5 GHz WiMAX operations is presented. The antenna is a coupled-fed PIFA and shows a height of 9 mm and a width of 13 mm only, when mounted at the top edge of the display panel in the laptop computer. The multiband operation is achieved by using the coupling feed and further embedding a band-notching slit in the radiating arm of the PIFA. With the coupling feed, two wide operating bands can be generated at about 2.5 and 5.5 GHz for the PIFA. By further embedding the slit of length about a quarter-wavelength at about 4 GHz, a band-notching characteristic at about 4 GHz is obtained, which leads to an additional resonance at about 3.5 GHz and shows very small effects on the desired 2.5 and 5.5 GHz bands. This behavior results in successful excitation of an additional resonant mode for 3.5 GHz WiMAX operation. Hence, with no increase in the antenna size, three wide operating bands for covering all the desired operating bands of WLAN/WiMAX systems are achieved for the proposed PIFA. Details of the design considerations are presented, and results of the fabricated prototype are discussed.

Internal WWAN Clamshell Mobile Phone Antenna Using a Current Trap for Reduced Ground Plane Effects

An internal wireless wide-area network (WWAN) antenna suitable for GSM850/900/1800/1900/UMTS operation in the clamshell mobile phone with reduced ground plane effects is presented. Small variations in the performances of the antenna for the clamshell mobile phone in the open state (talk condition) and closed state (idle condition) are obtained. This is owing to the reduced effects of the upper (cover) ground plane on the performances of the internal antenna obtained by embedding a slit at the edge of the upper ground plane close to the connecting strip between the two (upper and main) ground planes of the clamshell mobile phone. In this case, large surface currents excited around the slit are achieved, with other portions of the upper ground plane showing much weaker surface current distributions, which makes the embedded slit behaves like a current trap for the excited surface currents. This condition results in reduced effects of the upper ground plane. This also makes the near-field radiation of the clamshell mobile phone with the proposed antenna easily meet the specific absorption rate (SAR) and hearing aid compatibility (HAC) specifications required for practical applications.

Internal WWAN clamshell mobile phone antenna with reduced groundplane effects using a current trap

An internal WWAN antenna suitable for GSM850/900/1800/1900/UMTS operation in the clamshell mobile phone with reduced groundplane effects is presented. Small variations in the performances of the antenna in the open state and closed state are obtained. This is owing to the reduced effects of the upper ground plane on the performances of the internal antenna obtained by embedding a slit at the edge of the upper ground plane close to the connecting strip between the two ground planes of the clamshell mobile phone. In this case, large surface currents excited around the slit are achieved, with other portions of the upper ground plane showing much weaker surface current distributions, which makes the embedded slit behaves like a current trap for the excited surface currents.

Small-size printed coupled-fed PIFA with an embedded band-notching slit for internal WLAN/WiMAX laptop computer antenna

An internal printed antenna occupying a small size and covering all the operating bands of WLAN/WiMAX systems for laptop computer applications has been proposed and tested. The antenna is easy to fabricate on a thin FR4 substrate at low cost and shows a size of 9 × 13 mm2 only (not including the system groundplane dimensions), which is about the smallest among the related antennas in the published papers for covering WLAN and WiMAX operations in the wireless devices. The small size for the desired multiband operation is achieved owing to the use of the coupling feed and an embedded band-notching slit in the radiating arm of the proposed PIFA. Good radiation characteristics for frequencies over the operating bands have also been obtained. With the obtained results, the proposed PIFA is very promising for practical WLAN/WiMAX operations in the wireless devices, especially for the thin-profile laptop computers.

Broadband monopole antenna for DTV reception and gsm operation in the mobile phone

A broadband monopole antenna comprising a narrow radiating strip of length 120 mm and a simple internal matching portion for mobile phone application is presented. The monopole antenna can generate a wide operating band to cover the DTV reception in the UHF frequency band (470-862 MHz) and mobile communication in the GSM850/900 bands (824-894 MHz/890-960 MHz). The radiating strip is also promising to be retracted to be concealed inside the casing of the mobile phone when not in use. Details of the proposed antenna are described in the paper.

Study of promising internal WWAN antenna for the folder-type mobile phone with various chassis shapes

Stable performances of an internal WWAN antenna applied in the folder-type mobile phone with various chassis shapes are obtained. Six different states of the folder-type mobile phone, wherein the chassis shapes vary greatly, are studied. The WWAN antenna is mounted at the bottom of the main ground, and there are three connecting positions between the two grounds. For each operating states, the upper ground is connected to the main ground at one of the three connecting positions. At each position, a band-stop circuit is designed to excite a parallel resonance at around 900 MHz and leads to high impedance seen into the upper ground in the 900 MHz band. This greatly decreases the excited surface currents on the upper ground, making the presence of the upper ground have small effects on the performances of the WWAN antenna mounted at the bottom of the main ground. At around 1900 MHz, owing to its shorter wavelength, the surface currents on the upper ground excited by the WWAN antenna on the main ground are small. Thus, over both the 900- and 1900 MHz bands, the various orientations of the upper ground to the main ground cause small effects on the WWAN antenna embedded therein. Details of the obtained results are presented.

Erratum to "Uniplanar Printed Coupled-Fed PIFA With a Band-Notching Slit for WLAN/WiMAX Operation in the Laptop ComputerUniplanar Printed Coupled-Fed PIFA With a Band-Notching Slit"

-A small-size uniplanar printed antenna suitable for 2.4/5.2/5.8 GHz WLAN and 2.5/3.5/5.5 GHz WiMAX operations is presented. The antenna is a coupled-fed PIFA and shows a height of 9 mm and a width of 13 mm only, when mounted at the top edge of the display panel in the laptop computer. The multiband operation is achieved by using the coupling feed and further embedding a band-notching slit in the radiating arm of the PIFA. With the coupling feed, two wide operating bands can be generated at about 2.5 and 5.5 GHz for the PIFA. By further embedding the slit of length about a quarter-wavelength at about 4 GHz, a band-notching characteristic at about 4 GHz is obtained, which leads to an additional resonance at about 3.5 GHz and shows very small effects on the desired 2.5 and 5.5 GHz bands. This behavior results in successful excitation of an additional resonant mode for 3.5 GHz WiMAX operation. Hence, with no increase in the antenna size, three wide operating bands for covering all the desired operating bands of WLAN/WiMAX systems are achieved for the proposed PIFA. Details of the design considerations are presented, and results of the fabricated prototype are discussed.