Frances J. Harackiewicz

Miniature microstrip antenna with a partially filled high-permittivity substrate

A new technique to reduce the overall dimension of a microstrip antenna using a partially filled high-permittivity substrate is proposed. The miniaturized microstrip antenna for a repeater system in a mobile communication cellular band (824-894 MHz) is designed with the proposed technique and manufactured with light weight and small size. Comparison between simulations, based on HP HFSS software, and measurements are provided.

Magnetic tuning of a microstrip patch antenna fabricated on a ferrite film

A square, single-feed patch, fabricated on a ferrite film, that produced orthogonally polarized, well-formed radiation patterns is described. The application of a small in-plane magnetic field tuned the frequency, and hence phase, of one polarization only. Prior work on patch antennas fabricated on bulk ferrite substrates demonstrated magnetic tuning, but only linear polarization was obtained. The results indicate that (1) thin ferrite films, which are monolithically integrable, may be useful for a magnetically tunable antenna, and (2) the radiation polarization of the patch can be varied by the application of a small in-plane magnetic bias field.<<ETX>>

Compact UWB Antenna With I-Shaped Band-Notch Parasitic Element for Laptop Applications

A compact ultrawideband (UWB) antenna with a band-notch function is proposed for laptop applications. The band-notch function is realized by a half-wavelength parasitic element printed on the rear side of the substrate. The impedance bandwidth (VSWR < 2) of the antenna is 3.1 ~ 11.4 GHz (114%) with a notched frequency from 5.05 to 5.90 GHz. The antenna has a fairly good omnidirectional pattern, and the average gain is -3.0 ~ -1.2 dBi over the UWB frequency band except for the notched frequency band. The performance of the proposed antenna is confirmed by simulation and measurement results.

Ku-band high efficiency antenna with corporate-series-fed microstrip array

Excellent efficiency of a linearly polarized microstrip array in Ku-band is achieved by having proper impedance matching throughout the array and by properly using the corporate and series fed by microstrip transmission lines. The cavity-backed microstrip patch is used to obtain relatively wide bandwidth. The auto-tracking Ku-band antenna in the azimuth direction has developed with a very low profile for vehicles rooftop mounting, as well as, a low manufacturing cost. The main beam of array is tilted 15/spl deg/ away from the broadside direction to provide optimum coverage for Korea satellite III.

Closely Mounted Mobile Handset MIMO Antenna for LTE 13 Band Application

A compact (60 × 15 × 5 mm 3) mobile handset multiple-input-multiple-output (MIMO) antenna for LTE 13 band (746-787 MHz) applications is proposed. The antenna consists of two symmetrical planar inverted-F antennas (PIFAs) in conjunction with a T-shaped common radiator. Without using any additional coupling elements between these closely mounted antennas, both high isolation ( > 17 dB) and low envelope correlation coefficient (ECC <; 0.05 ) are achieved. The low ECC is achieved by using diagonally orthogonal radiation patterns from optimized locations of the MIMO antenna feeds and elements. Low mutual coupling achieved by using the T-shaped common radiator gives rise to the high isolation.

Balanced RFID Tag Antenna Mountable on Metallic Plates

A novel balanced tag antenna for a radio frequency identification (RFID) system is presented. The radiating elements of two planar inverted-F antennas (PIFAs) are inductively coupled by the feed loop with out of phase. The balanced structure provides smaller degradation of performances when an RFID tag is mounted on various sizes of metal plates. The HFSS simulator is employed to analyze the proposed antenna in the design process and to compare with measured results

NFC Antenna Design for Low-Permeability Ferromagnetic Material

A novel structure of a near-field communication (NFC) antenna for a mobile handset is proposed by changing the sequence of loop winding and modifying the inner loop structure. In general, the sintered ferrite sheets with higher relative permeability (μr ≈ 200) have been used to reduce the performance deterioration of NFC antennas due to the eddy current in the battery pack of a mobile handset. However, their costs are high, and they are considerably breakable. In this letter, we effectively enhance the performance of an NFC antenna by employing the ferrite-polymer composite with lower relative permeability (μr ≈ 55). The proposed antenna improves up to 23% more reading range and up to 65% better load modulation performance.

RFID tag antenna mountable on metallic plates

RFID tag antenna which could be mountable on metallic plate is designed and measured for 900MHz band. The proposed antenna consists of ground plane, substrate (/spl epsiv//sub r/ = 4.7), feed line with shorted circuit and radiating patch with L-shaped slit. The feed line with shorted circuit is designed for the direct impedance matching between the antenna and the RFID microchip. Especially, it is possible to obtain considerably the easy impedance match with the proposed design. Overall dimension of the proposed antenna is 90/spl times/54/spl times/5mm/sup 3/. When the antenna is placed in free space and mounted on 125/spl times/150mm/sup 2/, 250/spl times/300mm/sup 2/ metallic plates, the maximum reading distance is 6m, 4.8m and 5.2m, respectively.

Cavity-backed slot antenna array for the repeater system of a satellite digital multimedia broadcasting service

For the repeater system of the satellite digital multimedia broadcasting (DMB) service (2630/spl sim/2655 MHz) requiring a high-gain antenna and enough isolation between antennas, a cavity-backed slot antenna array (CBSAA) fed by a single waveguide is proposed to suppress side lobe level (SLL) and to increase front-to-back ratio (FBR). The SLL and FBR are enhanced with an optimized magnitude ratio of the electric field at each slot and an additional vertical reflector. The measured SLLs in the H- and E-planes are under -33.24 and -35.78 dB, respectively. An FBR over 37.84 dB and a peak gain over 17 dBi are measured. The proposed CBSAA consists of 2 /spl times/ 4 slot elements backed by a single cavity and has the characteristics of high power handling capability, high radiation efficiency, low feed line loss, and simple feed network.

The RCS of a microstrip antenna on an in-plane biased ferrite substrate

The numerical solutions for the RCS of a microstrip patch on an in-plane biased ferrite substrate are presented. The peaks in the RCS can be moved with respect to frequency by changing the magnetic bias field. We consider a monostatic RCS with various incident angles and examine all four elements of the cross-section matrix. For the case of an unmagnetized ferrite substrate the cross-polarized RCS components are zero. When the ferrite is magnetized, the cross-polarized RCS components become as significant as do the copolarized RCS components. It is also shown that a loaded patch has the effect of significantly reducing RCS at resonances. The analysis used is based on a full-wave moment method with the exact spectral-domain Greens function.