A monopolar patch antenna with a V-shaped slot for car-to-car (C2C) and wireless local area network (WLAN) communications is presented in this paper. To widen the impedance bandwidth of the antenna, techniques for adding a shorting pin and a V-shaped slot are applied to an equilateral triangular patch. By properly placing the shorting pins on an equilateral triangular patch, two operating modes, i.e., TM10 and TM20, are obtained. The presence of the V-shaped slot can generate an additional TM11 mode. These three resonances found in the operating frequency bandwidth resulted in a wideband characteristic. The proposed antenna can operate from 4.82 to 6.67 GHz for the reflection coefficient $\le -$ 10 dB with the gain of around 5.0 dBi. In addition, an omnidirectional radiation pattern is yielded by a coaxial center-fed probe excitation. The antenna has a thickness of 0.09 $\boldsymbol{\lambda}_\mathbf{g}$ (at the center frequency of 5.5 GHz), which is easily hidden on the roof of a vehicle for C2C communication. This proposed design can also be used as indoor base-station antennas for WLAN communication.

Bandwidth Enhancement of a Monopolar Patch Antenna With V-Shaped Slot for Car-to-Car and WLAN Communications

An octa-band WWAN/LTE monopole antenna with a size of $80\,\text{mm} \times 8\,\text{mm} \times 5.8\,\text{mm}$ for 5.7-inch mobile phones is proposed and studied. The proposed antenna consists of a folded metal plate with a lumped-element high-pass matching circuit. The working mechanism is analyzed based on the S-parameters and the surface current distributions. The 0.25-wavelength, 0.5-wavelength, and 1-wavelength modes of the monopole antenna are excited and used. The attractive merit of the proposed antenna is that the height of the nonground portion is only 8 mm. A prototype is fabricated and measured. Its measured $-6\;\text{dB}$ impedance bandwidths are 290 MHz (0.69–0.98 GHz) and 1.11 GHz (1.63–2.74 GHz) which cover the LTE700, GSM850, GSM900, GSM1800, GSM1900, UMTS, LTE2300, and LTE2500 bands. Within the two frequency bands, good radiation performances are obtained.

Wideband Monopole Antenna With Less Nonground Portion For Octa-Band WWAN/LTE Mobile Phones

A single-layered multiple-input multiple-output (MIMO) antenna system is presented for future wireless devices operating at WLAN (2.45 GHz, 5.2 GHz), 4G LTE (2.6 GHz) and 5G (24 GHz, 28 GHz) bands. The design consists of a dual-band four-element monopole MIMO antenna system that covers the 2.45 GHz and 5.2 GHz bands. A decoupling mechanism is designed in the ground plane based on a tapered slot. This tapered slot has a dual function, working both as a decoupling structure ( $\lambda _{0}/4$ long) at 2.45 GHz and as a tapered slot antenna ( $3\lambda _{0}$ long) at 28 GHz when excited by a proper feeder. The proposed MIMO antenna system is designed on an RO-5880 substrate with overall dimensions of $104$ mm $\times 104$ mm $\times 0.51$ mm. The measured results show that the presented design covers two low-frequency bands (from 2.40 GHz to 5.1 GHz, from 5.1 GHz to 5.6 GHz) with a peak gain of 5 dBi and one high-frequency band (from 23 GHz to 30 GHz) with a peak gain of 11 dBi. The minimum measured isolation between the two antennas is more than 16 dB, while the maximum envelope correlation coefficient value is less than 0.16 showing good MIMO characteristics.

Multiband MIMO Microwave and Millimeter Antenna System Employing Dual-Function Tapered Slot Structure

A small-size tablet device antenna formed by a simple folded metal plate excited by a low-band feed (direct feed with matching network) and a high-band feed (gap-coupled feed with matching network) for the LTE/WWAN operation in the 698–960 and 1710–2690 MHz bands is presented. The folded metal plate has a size of 3 $\, \times \,$ 5 $\, \times \,$ 30 mm $^{3}$ and is disposed in a clearance area of 10 $\, \times \,$ 30 mm $^{2}$ (300 mm $^{2}$ ) above the top edge of the device ground plane. The matching network in the low-band feed compensates for additional capacitance for the folded metal plate with a resonant length much less than 0.25 wavelength in the lower band (698–960 MHz) and enhances the antenna's impedance matching to achieve a wide lower band. The matching network in the high-band feed also enhances the antenna's impedance matching to achieve a wide higher band (1710–2690 MHz). In addition, the coupling gap in the high-band feed can reject the low-band frequency. Also, the matching network in the low-band (high-band) feed includes a bandpass circuit which can help reject the high-band (low-band) frequency. Good isolation between the two hybrid feeds can, hence, be obtained, which makes the antenna with simple structure and small size have good radiation performances in both lower and higher bands. Details of the proposed antenna are presented.

Small-Size LTE/WWAN Tablet Device Antenna With Two Hybrid Feeds

This thesis focuses on mobile phones antenna design with brief description about the historical development, basic parameters and the types of antennas which are used in mobile phones. Mobile phones antenna design section consists of two proposed PIFA antennas. The first design concerns a single band antenna with resonant frequency at GPS frequency (1.575GHz). The first model is designed with main consideration that is to have the lower possible PIFA single band dimensions with reasonable return loss (S11) and the efficiencies. Second design concerns in a wideband PIFA antenna which cover the range from 1800MHz to 2600MHz. This range covers certain important bands: GSM (1800MHz & 1900MHz), UMTS (2100MHz), Bluetooth & Wi-Fi (2.4GHz) and LTE system (2.3GHz, 2.5GHz, and 2.6GHz). The wideband PIFA design is achieved by using slotted ground plane technique. The simulations for both models are performed in COMSOL Multiphysics. The last two parts of the thesis present the problems of mobile phones antenna. Starting with Specific absorption rate (SAR) problem, efficiency of Mobile phones antenna, and hand-held environment.

/pdf/mobile-phone-antenna-design-1w0bdhvfh8.pdf

Mobile Phone Antenna Design

A compact ground radiation method for 2.45 and 5.5 GHz wireless local area network (WLAN) applications is proposed. This method is based on two different loop-type current modes that are excited in the ground plane and separately operated at 2.45 and 5.5 GHz, producing a very small-sized antenna with good radiation efficiencies and wide impedance bandwidths. The proposed radiation method requires a small ground clearance of 8.5 mm × 4.5 mm for installing the antenna element. The experimental result shows that a good impedance matching performance is simultaneously achieved at the dual frequency bands and the -10 dB bandwidths are obtained as 120 MHz and 720 MHz at the 2.45 and 5.5 GHz frequency bands, respectively, and good radiation performance is achieved.

Loop-Type Ground Radiation Antenna for Dual-Band WLAN Applications

A loop-type ground antenna, designed as a rectangular ground clearance connected by a capacitor, is proposed for mobile devices. The electromagnetic mechanism underlying the antenna operation is based on a new feeding method; a capacitor is used to cause a current loop to resonate at the operating frequency band. The proposed antenna is 5 × 3 mm and is easily implemented within mobile devices. The -10 dB bandwidth of the antenna is 400 MHz, from 2.3 to 2.7 GHz. The radiation pattern it produces shows omnidirectional performance on the horizontal plane.

Loop-type ground antenna using resonated loop feeding, intended for mobile devices

A multi-resonance feed structure for exciting a mobile handset antenna in order to achieve multiband operation is presented. The feed structure adjusts its impedance and controls the coupling with the antenna structure. Based on the proposed feed structure, the dimensions allowed for the antenna design are only 10 × 55 × 2 mm 3
 while the measured impedance bandwidth is from 694 to 1003 MHz in the lower band and from 1656 to 2772 MHz in the higher band under a voltage standing wave ratio of 3:1 with good measured realized efficiency. The proposed antenna is a competitive candidate that fully covers most 4th generation (4G) and existing wireless communication services.

Mobile Antenna Using Multi-Resonance Feed Structure for Wideband Operation

An innovative antenna radiation method for exciting a dipole-type radiation mode in the ground plane of mobile devices is proposed. This method is based on a capacitively loaded slot placed at the centre of the ground plane. The ground plane is 50 × 15 mm in length and width, respectively, which is the size typically used in USB dongles and headsets. The −10 dB impedance bandwidth is 12.9% at 2.4 GHz, fully covering the WiMax, Wi-Fi and Bluetooth frequency bands.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/el.2012.4520

Ground radiation method using slot with coupling capacitors

A loop-type ground antenna with wide-band operation is proposed for USB dongle applications. The solution for improving the bandwidth is based on a resonant feeding circuit that includes both an inductor and a capacitor. By choosing an appropriate ratio of the inductance to the capacitance, the impedance bandwidth (VSWR < 2) is 21.8% at 2.2 GHz, sufficient bandwidth to cover both the WCDMA and WiMax frequency bands.

Yang Liu

Papers

Loop-Type Ground Radiation Antenna for Dual-Band WLAN Applications

Loop-type ground antenna using resonated loop feeding, intended for mobile devices

Mobile Antenna Using Multi-Resonance Feed Structure for Wideband Operation

Ground radiation method using slot with coupling capacitors

Bandwidth enhancement of ground antenna using resonant feeding circuit