Parasitic Shorted Strip Research Articles

A Broadband Antenna Based on a Single CRLH TL Unit Cell and a Parasitic Strip for Sub-1GHz DVB and LTE Applications

A Broadband and slim profile antenna based-on a single composite right/left-handed transmission line unit cell and parasitic shorted strip is presented for sub-1 GHz digital video broadcasting and long-term evolution applications (470-970 MHz). It is comprised of an ungrounded coplanar waveguide that feeds a meandered strip (distributed series inductors), which is connected through capacitive coupling (series capacitance) with a virtual small ground, while an upper shorted meandered strip represents a parallel inductor. A shorted meandered strip (parasitic inductor) is added to create a third resonant frequency. A broadband operation is achieved by merging three different resonant modes frequencies (zeroth-order mode and two quarter wavelength monopole modes) to satisfy 6 dB bandwidth criterion. A prototype is constructed and measured in order to verify the achieved results. The results of reflection parameter, gain, efficiency, patterns and bandwidth efficiency product are presented, discussed, and evaluated with respect to literature. The results show that the proposed antenna is a potential candidate for recent broadband digital video broadcasting applications.

Planar Monopole Antenna With a Parasitic Shorted Strip for Multistandard Handheld Terminals

A planar monopole antenna with a parasitic shorted strip for multistandard handheld terminal is presented. The proposed antenna simply consists of two overlapping strips: a long strip on the front side and a parasitic shorted strip on the back side. To make the proposed antenna easy to manufacture and reduce the manufacturing cost, the entire structure is fully printed without VIA holes, the long strip monopole is directly fed, and the parasitic shorted strip is coupled-fed by the overlapped part. For lower and middle frequencies, the GSM900 and PCS bands are excited by the fundamental mode of the long strip and the parasitic shorted strip, respectively. For the upper frequency, the Wi-Fi2400/RFID2450 and LTE2300/2500 bands are provided by the third-order mode of the long strip. The detailed design of the proposed antenna and its radiation performances are studied. The proposed multiband antenna occupies a small area of $40 \times 18$ mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> on a printed circuit board (PCB). The measured results show that the proposed antenna has three impedance bands with return loss less than -6 dB: 25.6% for the low band (850-1100 MHz), 13.3% for the middle band (1750-2000 MHz) and 22.7% for the high band (2190-2750 MHz).

A novel uniplanar antenna with dual wideband characteristics for tablet/laptop applications

A novel uniplanar antenna design for tablet/laptop applications is proposed. The proposed antenna with a size of 68 × 12 × 0.8 mm3 is comprised of three strip sections, namely, the feeding strip, parasitic shorted strip, and tuning stub strip (or printed LC matching circuit). Five resonant modes are induced by the proposed antenna, and they are combined to yield two wide operating bands that have 6-dB return loss bandwidths of more than 50% (695-1190 MHz and 1690-2930 MHz). Thus, the proposed antenna can easily cover the entire LTE/WWAN operations working in the 698-960 MHz and 1710-2690 MHz bands. Besides demonstrating good radiation efficiency of more than 60% for the two wide operating bands, the proposed antenna also exhibits reduced ground effects, in which reducing the ground size will not deteriorate the antenna's performances.

Small‐size reconfigurable antenna for WWAN/LTE/GNSS smartphone applications

A small-size reconfigurable smartphone antenna using a PIN diode for WWAN/LTE and global navigation satellite system (GNSS) smartphone application is presented. When the diode is in `OFF' state, a T-shaped feeding strip and an encircled T-shaped parasitic shorted strip formed a coupled-fed antenna, which achieves a low-wideband covering GSM850/900 bands and a high-wideband covering GSM1800/1900/UMTS2100/LTE2300/2500 bands. When the diode is in `ON' state, a loop antenna working at 1/2 wavelengths is formed to cover the bands of GNSS, which includes four positioning systems (COMPASS, GALILEO, GPS and GLONASS). In addition, the proposed antenna is easily printed on a small ground clearance of 375 mm 2 without loading any lumped element. Also, the proposed simple and compact antenna is convenient to be optimised for desired bands. Finally, the good agreement of simulated and experimental results proves that the proposed antenna is suitable for practical mobile terminal equipment.

Frequency reconfigurable antenna for hand‐held wireless devices

In this communication, a balanced frequency-reconfigurable antenna for nine-band operation covering GSM 850/900/1800/1900/UMTS2100/LTE700/2300/2500 /WLAN2400 bands for multiradio mobile platforms is presented. The antenna consists of simple planar geometry with size of 60 × 15 mm2 that is quite practical for implementation on current consumer-type multiradio mobile platforms. The design comprises of a feeding strip and an electromagnetically coupled parasitic shorted strip whose effective length is electronically controlled through a single PIN diode. By combining both ON and OFF states of the PIN diode, four resonance modes are achieved covering nine bands of LTE/WWAN/WLAN operation. The proposed antenna is successfully simulated, fabricated and measured. It has excellent radiation efficiency and positive gains over all nine bands of operation.

Small-Size Octaband Monopole Antenna in an LTE/WWAN Mobile Phone

This letter proposes a small-size printed antenna with multiband WWAN/LTE operation in a mobile phone by introducing a novel loop parasitic shorted strip and a C-shaped ground plane. The obtained impedance bandwidths across LTE and WWAN operating bands approach 277 and 1176 MHz, respectively. The proposed printed monopole antenna reduces the antenna size by at least 22% since the overall antenna size is only 35 × 10 × 0.8 mm3. The measured peak gains and antenna efficiencies are approximately 2.2/3.1 dBi and 76%/82% for the LTE/WWAN bands, respectively.

Simple Printed WWAN Monopole Slot Antenna with Parasitic Shorted Strips for Slim Mobile Phone Application

ABSTRACTIn this article, a simple printed monopole slot antenna with two parasitic shorted strips (a longer parasitic shorted strip and a shorter parasitic shorted strip) for penta‐band wireless wide area network operation in the slim mobile phone is presented. The monopole slot has a length of 40 mm only and is disposed near the bottom edge of the system ground plane of the mobile phone with a small distance of 6.5 mm. By adding longer parasitic shorted strip connected to the bottom corner edge of the system ground plane, good excitation of the monopole slot antenna at its fundamental (quarter‐wavelength) mode and chassis dipole‐type mode of the system ground plane can be obtained. The shorter parasitic shorted strip contributes additional resonant mode to the antenna. The excited resonant modes form two wide operating bands to cover the GSM850/900 operation (824–960 MHz) and GSM1800/1900/WCDMA Band I operation (1710–2170 MHz), respectively. Details of the proposed antenna are presented. The specific absorption rate results for the antenna with the presence of the head and hand phantoms are also studied. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2835–2841, 2013

Planar Internal LTE/WWAN Monopole Antenna for Tablet Computer Application

By using a T-shaped parasitic shorted strip, this work presents a planar coupled-fed U-shaped monopole antenna with eight-band LTE/WWAN operation in tablet computers. The obtained impedance bandwidths across dual operating bands approach 281 MHz and 1088 MHz at the LTE and WWAN bands, respectively. The proposed uniplanar antenna reduces the antenna size by at least 20% since the overall antenna size is only 50×15×0.8 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The measured peak gains and antenna efficiencies are approximately 2.9/5.4 dBi and 72/80% for the LTE/WWAN bands, respectively. Moreover, with a compact structure, the proposed planar antenna can be deposited inside the tablet computer and complies with the body specific absorption rate (SAR) requirement (1.6 W/kg for 1-g body tissue) for practical applications.

Small-Size Planar LTE/WWAN Antenna and Antenna Array Formed by the Same for Tablet Computer Application

For eight-band LTE/WWAN operation (704–960/1710–2690 MHz) in the Ultrabook or thin-profile tablet computer, a planar antenna of simple structure and small size is presented. The proposed antenna is obtained by modifying a simple planar inverted-F antenna and can be printed on one surface of a thin FR4 substrate of size 10 × 45 mm2 only. The antenna's lower band bandwidth is greatly widened by embedding a proper chip capacitor of 2.7 pF at the feeding strip. This chip capacitor combines with the antenna's shorting strip can control the excitation of a parallel resonance to modify the impedance matching of the antenna's lower band such that a widened bandwidth is easily obtained to cover the LTE700/GSM850/900 operation. Conversely, the antenna's upper-band bandwidth is also greatly enhanced by using a coupled section in the antenna's radiating strip and adding a parasitic shorted strip near the feeding strip, which lead to multiple resonant modes excited to form a wide bandwidth (>1 GHz) to cover the GSM1800/1900/UMTS/LTE2300/2500 operation. Owing to its small size and simple structure, the proposed antenna is very suitable to be applied in achieving an antenna array with high isolation for MIMO or dual talk (dual WWAN) operation. Promising high-isolation antenna arrays formed by the proposed antennas are presented. The obtained isolation between the antennas in the antenna array is better than 12 dB, and the envelope correlation coefficient is less than 0.15 for frequencies over the LTE/WWAN bands. Details of the proposed antenna and antenna array are presented. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1928–1934, 2013

Bandwidth Enhancement of Small-Size Planar Tablet Computer Antenna Using a Parallel-Resonant Spiral Slit

An internal planar tablet computer antenna having a small size of 12 × 35 mm2 printed on a 0.8-mm thick FR4 substrate for the WWAN operation in the 824-960 and 1710-2170 MHz bands is presented. The antenna comprises a driven strip, a parasitic shorted strip and a ground pad, all printed on the small-size FR4 substrate. For bandwidth enhancement of the antenna's lower band, the antenna applies a parallel-resonant spiral slit embedded in the ground pad, which generates a parallel resonance at about 1.2 GHz and in turn results in a new resonance occurred nearby the quarter-wavelength mode of the parasitic shorted strip. This feature leads to a dual-resonance characteristic obtained for the antenna's lower band, making it capable of wideband operation to cover the desired 824-960 MHz with a small antenna size. The antenna's upper band is formed by the higher-order resonant mode contributed by the parasitic shorted strip and the quarter-wavelength resonant mode of the driven strip and can cover the desired 1710-2170 MHz band. Details of the proposed antenna and the operating principle of the parallel-resonant spiral slit are presented.

Low‐profile, small‐size, wireless wide area network handset antenna close integration with surrounding ground plane

AbstractAn internal wireless wide area network (WWAN) handset antenna having a low profile of 3 mm, small footprint of 30 × 10 mm2, and closely integrated with surrounding ground plane is presented.The antenna volume is 0.9 cm3 only and can provide two wide‐operating bands to cover the desired 824–960 and 1710–2170 MHz bands. The major portion of the antenna is printed on the main circuit board of the handset, and the antenna has a simple structure formed by a strip monopole and a parasitic shorted strip monopole. Two techniques are applied in the proposed design to achieve penta‐band WWAN operation with a small antenna size. The first technique is to load a proper chip inductor at a proper position in the shorted strip monopole, which supports a resonant mode for the antenna's lower band with a resonant length much smaller than 0.25‐wavelength. The second one is to use a band‐stop matching circuit disposed on the main circuit board of the handset. The combined effects of the two techniques are discussed in this article. Also, the proposed antenna shows low near‐field radiation characteristic and meets the specific absorption rate and hearing‐aid compatibility requirements for practical handset applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:623–629, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26633

Magneto-electric monopole antenna for terminal multiband applications

Presented is a multiband terminal antenna providing two wide bands for covering seven-band LTE/GSM/UMTS operation. This new antenna comprises an electric monopole with parasitic shorted strip and two back-to-back slot monopoles, which can be seen as magnetic monopoles. The two slot monopoles are excited by the coupling of two microstrip stubs on the back side, and the electric monopole is connected to the microstrip feeding line directly. A prototype has been constructed and tested. Simulated and measured results are given.

Small‐size multiband planar antenna for LTE700/2300/2500 operation in the tablet computer

AbstractA small‐size multiband planar antenna can be obtained using a long parasitic shorted strip and a monopole feed encircled by the same. Such a configuration can lead to a small antenna size for multiband operation, and a promising design with a small size of 12 × 35 mm2 for covering three‐band LTE700/2300/2500 operation (704–787/2300–2400/2500–2690 MHz bands) in the tablet computer is presented. The antenna is easy to fabricate on one surface of an FR4 substrate and is composed of an inverted‐L strip as the monopole feed and a long parasitic shorted strip encircling the inverted‐L monopole. The long shorted strip is parasitically excited to generate a 0.25‐wavelength resonant mode at about 750 MHz to cover the LTE700 operation, while the inverted‐L monopole generates a 0.25‐wavelength resonant mode at about 2.5 GHz to cover the LTE2300/2500 operation. Details of the proposed antenna are described. Radiation characteristics of the antenna and its body specific absorption rate results for tablet computer applications are also presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:81–86, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26507

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.

On-board small-size printed LTE/WWAN mobile handset antenna closely integrated with system ground plane

An on-board uniplanar printed mobile handset antenna with a small size of 15 × 30 mm2 for 8-band long term evolution/wireless wide area network (LTE/WWAN) (698–960/1710–2690 MHz) operation is presented.The antenna is a spiral monopole coupled with a long parasitic shorted strip. The spiral monopole has a length of 78 mm (about 0.25 wavelength at 950 MHz), while the shorted strip capacitively excited by the spiral monopole has a length of 125 mm (close to 0.25 wavelength at 700 MHz). The spiral monopole is encircled by the shorted strip so that the antenna has a compact configuration to fit in a small no-ground portion at the corner of the bottom edge of the main circuit board in the mobile handset. In addition, the antenna is closely integrated with the system ground plane on the main circuit board and is spaced by a small distance of 0.5 mm to the nearby system ground plane. This leads to compact integration of the on-board LTE/WWAN printed antenna on the main circuit board of the mobile handset. Results of the proposed antenna including its specific absorption rate and hearing aid compatibility behavior are presented and discussed. The antenna is about the smallest for the on-board all-printing LTE/WWAN handset antennas that have been reported for the present. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1336–1343, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25961

Simple two‐strip monopole with a parasitic shorted strip for internal eight‐band LTE/WWAN laptop computer antenna

AbstractA dual‐wideband internal antenna formed by a simple two‐strip monopole (a longer strip and a shorter strip) and a parasitic shorted strip for eight‐band long tern evolution/wireless wide area network operation (698–960/1710–2690 MHz) in the laptop computer is presented.The parasitic shorted strip is excited capacitively by the shorter strip of the two‐strip monopole and contributes two resonant modes to the antenna, with one in the lower band and one in the upper band, thereby effectively widening the bandwidths of the antenna's two operating bands. Further, the parasitic strip short‐circuited to the top shielding metal wall of the display ground in the laptop computer is configured such that its end section with the shorting point is positioned at the side edge of the antenna. This configuration allows the antenna to be placed closely to a nearby grounded plate, with very small effects on the performances of the antenna. This is an advantage for the proposed antenna in practical applications since the antenna requires a very small isolation distance at its side edge to nearby metal objects (such as a metal screw at the top shielding metal wall to fix the display ground to the casing of the laptop computer). Hence, in addition to the small antenna volume of 4 × 12 × 70 mm3 at the top shielding metal wall, compact integration of the proposed antenna along the shielding metal wall of the display ground can also be obtained. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:706–712, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25836

Planar Printed Strip Monopole With a Closely-Coupled Parasitic Shorted Strip for Eight-Band LTE/GSM/UMTS Mobile Phone

A planar printed antenna comprising a driven strip monopole and a parasitic shorted strip, both of comparable length and closely coupled to each other, suitable for eight-band LTE/GSM/UMTS operation in the mobile phone is presented. The proposed antenna is mainly configured along the boundary of the no-ground portion on the system circuit board of the mobile phone to achieve a simple and compact structure. Also, the edge of the no-ground portion facing the system ground plane on the circuit board is not necessarily a straight line, leading to more degrees of freedom in allocating the required no-ground portion on the circuit board for printing the antenna. The driven strip monopole and the parasitic shorted strip both contribute their lowest and higher-order resonant modes to form two wide operating bands centered at about 830 and 2200 MHz to respectively cover the LTE700/GSM850/900 operation (698-960 MHz) and GSM1800/ 1900/UMTS/LTE2300/2500 operation (1710-2690 MHz).

Wideband printed monopole antenna integrated in a system in package

A promising design of integrating a wideband printed monopole antenna in a system in package (AiSiP) for wireless local area network (WLAN) operation in the 2.4 GHz band is presented. The antenna is an inverted-F monopole antenna printed on the no-ground portion (6 × 18 mm2) of the module substrate of the AiSiP (total size 24 × 18 mm2). A parasitic shorted strip can also be added in the no-ground portion to double the operating bandwidth of the AiSiP. When mounted on the system ground plane of a wireless device, the AiSiP can provide a complete communication function, without the need of employing additional antennas in the wireless device. The proposed AiSiP is studied in the paper, and obtained results of the constructed prototype are presented. Effects of the system ground plane on the antenna performance of the AiSiP are also analyzed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2113–2117, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21868