Jong-Myung Woo

A Compact Ultrawideband MIMO Antenna With WLAN Band-Rejected Operation for Mobile Devices

This letter presents an ultrawideband multiple-input-multiple-output (MIMO) antenna that covers the WCDMA (1.92-2.17 GHz), WiMAX (2.3, 2.5 GHz), WLAN (2.4 GHz), and UWB (3.1-10.6 GHz) bands for wireless device applications. The proposed antenna consists of a printed folded monopole antenna coupled with a parasitic inverted-L element, with an open stub inserted in the antenna to reject the WLAN (5.15-5.85 GHz) band that interferes with the UWB band. These two antennas are symmetrically arranged on a mobile device substrate. The -10-dB bandwidth of the designed antenna is 1.85-11.9 GHz without the WLAN band 5.15-5.85 GHz. S21 and the envelope correlation coefficient are lower than -17.2 dB and 0.18 in the operating bands, respectively. The size of the antenna is 55 ×13.5 × mm2.

A Miniaturized, Dual-Band, Circularly Polarized Microstrip Antenna for Installation Into Satellite Mobile Phones

A miniaturized, dual-band, circularly polarized microstrip antenna (CPMA) for satellite mobile phones was designed. Two miniaturized radiation elements using folded structures are stacked vertically to achieve dual bands. Each radiation element shows left-handed circular polarization. The total volume of this dual-band, circularly polarized, microstrip antenna is 46 mm (length) x 24 mm (width) x 13 mm (height). The overall antenna is mounted on a phone-shaped ground plane to fit inside satellite mobile phones.

Compact Multiband Microstrip Antenna Using Inverted-L- and T-Shaped Parasitic Elements

By placing inverted-L- and T-shaped parasitic elements at both the radiating apertures of a microstrip patch antenna, a low-profile, compact single-layer multiband microstrip antenna operable in various bands has been developed. These bands include LTE TDD No. 34 (2.0175 GHz), WLAN (2.45 GHz), and WiMAX (3.5 GHz) bands. The antenna has dimensions of 0.26 λ_L ×0.25 λ_L ×0.03 λ_L, where λ_L is the free-space wavelength at 2.0175 GHz, and resonance in the parasitic elements occurs through coupling and perturbations to the microstrip patch. In each band, the measured -10-dB bandwidths cover the required bandwidths at 28 MHz (1.39%), 91 MHz (3.71%), and 255 MHz (7.29%). Within each of the designed bands, a broadside radiation pattern is observed.

An Electrically Small Spherical UHF RFID Tag Antenna With Quasi-Isotropic Patterns for Wireless Sensor Networks

An electrically small spherical UHF (911.25 MHz) radio frequency identification (RFID) tag antenna is proposed. A dipole-typed RFID tag antenna is wound into a spherical shape to achieve small size and quasi-isotropic pattern. The overall diameter of the antenna is 25 mm (0.076¿), and the resulting electrical size is a kr of 0.24. A short stub is employed for good conjugate impedance matching with a RFID chip (Zchip = 14 - j145 ¿). The designed antenna has a -10-dB bandwidth of 7 MHz (0.77%) and the maximum readable distance of 132 cm at 5.2 W EIRP.

Size Reduction in UHF Band RFID Tag Antenna Based on Circular Loop Antenna

In this paper, small-sized RFID tag antenna is designed and fabricated based on the circular loop antenna used in UHF band (860-960 MHz). The tag antenna with its center frequency at 911.25 MHz (wave length lambda: 329 mm) adopts a parallel transmission line feed method to match the impedance and reduces its size using a stub. As a result, the antenna (diameter lambda: 54 mm) with 15 stubs reduces its size up to 69.6% compared with the one without any stub. The measured return loss is -9.942 dB, -3 dB bandwidth is 84.35 MHz(9.26%) and the gain in z-x plane is -0.37 dBd. The radiation pattern shows a magnetic dipole antenna characteristic and omnidirectional pattern in horizontal plane

Miniaturization of microstrip antenna using folded structure with attaching plates for satellite communication terminal

Today, the advancement speed of wireless communication system is accelerated and consumers want a communication service without limit of space. A portable satellite communication service is required with the need and miniaturization of a mobile terminal is more important. The previous antenna for a satellite communication terminal, such as the Quadrifilar Helix antenna, is used but it is not suitable for portable by its huge volume To solve this problem, in this paper, miniaturizing a microstrip patch antenna with 3-dimensional structure is explained that it has a small volume, a low position, light weight, and mass production. Generally, since the size of a microstrip patch antenna is in proportion with the wavelength of a center frequency, a high permittivity dielectric is utilized for miniaturization of an antenna. However, this method causes drops of a radiating efficiency and bandwidth by the high permittivity. Therefore, folded structure and a method of using a plate attached in the bottom of an antenna are mixed rather than using a high dielectric. It is that a plate is attached on the edge of a folded antennas patch. Also, to minimize an antenna, a method of folded structure is applied to resonance length L and width W in a general patch antenna.

Interferometer Direction-Finding System With Improved DF Accuracy Using Two Different Array Configurations

A novel array configuration for improving the direction-finding (DF) accuracy of an interferometer DF system is presented. The interferometer DF system that uses a single array configuration provides a high DF accuracy over a wide frequency range. However, the DF accuracy in the low-frequency range for this array configuration is lower than that of the high-frequency range. The use of a different array configuration and spacing according to the frequency range or the extension of the widest baseline in the low-frequency range by the addition of an antenna can be applied to overcome this limitation. With the proposed method, the DF accuracy in the low-frequency band is improved while the DF accuracy in the high-frequency band is maintained. Simulation results for some examples are presented to demonstrate the effectiveness of the proposed array configuration.

Microstrip Line Monopole Antenna for the Wearable Applications

A low-profile microstrip line monopole antenna (MLMA) has been proposed that can be used as a wrist-wearable antenna for the UHF band RFID system (911.25 MHz). This suggested antenna was designed as a 15 mm wide, 100 mm long and 0.6 mm thick monopole structure with quarter wave-length short stubs disposed in parallel on both sides of the microstrip line on the ground plane and with the end of the microstrip line extended by 0.14lambda. As a result of the characteristic measurements, the S11 and maximum gain were shown to be -14 dB (-10 dB bandwidth: 14 MHz, 1.53%) and -7.5 dBd, respectively.

Miniaturization of microstrip line monopole antenna for the wearable applications

In this paper, we present a miniaturized microstrip line monopole antenna(MLMA) using folded structure for a wearable antenna in Korean UHF band RFID system(operating frequency: 911.25MHz, bandwidth: 5.5MHz, wavelength lambda:329mm), which is highly capable of tracking and detecting due to its long read range. The suggested wearable antenna was designed as a low-profile antenna with a ground plane in order to minimize the effect of the human body. For the antenna to be wrist-wearable, the following requirements were considered for its design: a narrow small-size ground plane, a flexible substrate, an appropriate antenna gain, and a low price.

Surface-mounted chip dielectric ceramic antenna for PCS phone

In the telecommunication market smaller and lighter devices are preferred in order to miniaturize devices such as antennas, filters and duplexers, multi-layered microwave devices. The realization of these devices may be accomplished by integration of electromagnetic wave analysis technology and the manufacturing technology of dielectric materials. Furthermore, low-fire microwave ceramics which can be co-fired with good conductors such as silver metal, are needed. The microwave dielectric properties of ZnNb/sub 2/O/sub 6/ and Pb/sub 5/Nb/sub 4/O/sub 15/ (ZNPN ceramics) with additives (CuV/sub 2/O/sub 6/, Sb/sub 2/O/sub 3/ and glass) was investigated. A chip antenna (7.5 mm/spl times/4.5 mm/spl times/0.8 mm) using a multilayered process was designed (1.91 GHz for PCS) and manufactured.