A planar monopole antenna with a staircase shape and small volume (25times26times1 mm3) is proposed in this paper. With the use of a half-bowtie radiating element, the staircase-shape, and a modified ground plane structure, the proposed antenna has a very wide impedance bandwidth measured at about 11.6 GHz (2.9-14.5 GHz, bandwidth ratio about 1:5) below VSWR 2 including the WLAN band notched in the vicinity of 5 GHz. An omnidirectional radiation pattern is obtained. The group delay which is an indication of linearity between two proposed antennas is less than 1 ns. The electrical characteristics in terms of frequency and time domains and physical ones of the proposed antenna make it attractive for use in ultrawideband (UWB) systems

A miniature UWB planar monopole antenna with 5-GHz band-rejection filter and the time-domain characteristics

A simple and compact ultrawideband (UWB) aperture antenna with extended band-notched designs is presented. The antenna consists of a rectangular aperture on a printed circuit board ground plane and a T-shaped exciting stub. The proposed planar coplanar waveguide fed antenna is easy to be integrated with radio-frequency/microwave circuitry for low manufacturing cost. The antenna is successfully designed, implemented, and measured. A compact aperture area of 13 times23mm2 is obtained with promising performances, including broadband matched impedance, stable radiation patterns, and constant group delay. The correlation between the mode-based field distributions and radiation patterns is discussed. Extended from the proposed antenna, three advanced band-notched (5-6 GHz) designs are also presented as a desirable feature for UWB applications

Compact Ultrawideband Rectangular Aperture Antenna and Band-Notched Designs

Wideband planar monopole antennas with dual band-notched characteristics are presented. The proposed antenna consists of a wideband planar monopole antenna and the multiple cup-, cap-, and inverted L-shaped slots, producing band-notched characteristics. In order to generate dual band-notched characteristic, we propose nine types of planar monopole antennas, which have two or three cap (cup or inverted L)-shaped slots in the radiator. This technique is suitable for creating ultra-wideband antenna with narrow frequency notches or for creating multiband antennas

Wideband planar monopole antennas with dual band-notched characteristics

The paper presents a study of coplanar waveguide (CPW) fed circular disc monopole antenna for ultra-wideband (UWB) applications. A circular disc monopole printed on a dielectric substrate and fed by a 50 /spl Omega/ CPW on the same layer can yield an ultra-wide -10 dB return loss bandwidth with satisfactory radiation patterns. The performance and characteristics of the antenna are investigated in order to understand its operation. Good agreement has been obtained between the simulation and experiment.

http://ap-s.ei.tuat.ac.jp/isapx/2004/pdf/1B2_4.pdf

Study of CPW-fed circular disc monopole antenna for ultra wideband applications

A broadband circularly polarized patch antenna is proposed for universal ultra-high-frequency (UHF) RF identification (RFID) applications. The antenna is composed of two corner-truncated patches and a suspended microstrip line with open-circuited termination. The main patch is fed by four probes which are sequentially connected to the suspended microstrip feed line. The measurement shows that the antenna achieves a return loss of -15 dB, gain of 8.3 dBic, axial ratio (AR) of 3 dB, and 3-dB AR beamwidth of 75deg over the UHF band of 818-964 MHz or 16.4%. Therefore, the proposed antenna is universal for UHF RFID applications worldwide at the UHF band of 840-960 MHz. In addition, a parametric study is conducted to facilitate the design and optimization processes for engineers.

A Universal UHF RFID Reader Antenna

A novel ultra-wideband (UWB) tapered slot antenna (TSA) is proposed that has both enhanced impedance bandwidth enough to cover UWB systems and band cutoff characteristic of 5 GHz WLAN band limited by IEEE802.11a and HIPERLAN/2. To achieve these two characteristics of wide bandwidth and partial band cutoff at the TSA, a broadband microstrip-slotline transition with multi-arm stubs and /spl lambda//4 short stubs, respectively, is used. From measured results, it is observed that wide bandwidth of about 2 octaves from 2.8 to 11.09 GHz for the VSWR<2 is achieved, while 5.05-5.93 GHz is cutoff with the radiated power of this cutoff band effectively suppressed as about -9 dB for the peak power level of other bands.

Ultra-wideband tapered slot antenna with band cutoff characteristic

A single series feed cross-aperture coupled microstrip antenna with the effect of hybrid feeding is proposed and demonstrated. To understand this antenna better, the characteristics according to the variation of parameters are shown. This proposed antenna has the following advantages of the effect of hybrid feeding: improved axial ratio bandwidth (4.6%); high gain (8 dBi); flat 3 dB gain bandwidth (above 16.7%). In measured radiation patterns, we have 3 dB beamwidth of /spl plusmn/30/spl deg/ and good F/B (front to back ratio) of 20 dB.

A single-feeding circularly polarized microstrip antenna with the effect of hybrid feeding

This paper proposes a novel ultra-wideband antenna that has the omni-directional pattern in azimuth and the band-rejection characteristic of the 5.15/spl sim/5.825 GHz band limited by IEEE 802.11a and HIPERLAN/2. The proposed antenna is the circular monopole type with two slits and fed by a CPW line, and it satisfies the UWB band, 3.1/spl sim/10.6 GHz for VSWR < 2.

A study on the UWB antenna with band-rejection characteristic

This paper proposes a novel ultra wideband (UWB) tapered slot antenna (TSA) to achieve both enhanced impedance bandwidth for UWB RF front-ends and band-stop characteristics in the 5 GHz WLAN band, limited by IEEE802.11a and HIPERLAN/2. To obtain these two characteristics of wideband and band-stop in the TSA, a broadband microstrip-slotline transition with multi-arm stubs and /spl lambda//4 short stubs are used respectively. From the measured results, it can be shown that a wide bandwidth of 1.99 octaves from 2.8 to 11.09 GHz for a VSWR<2 is obtained while the 5.0 /spl sim/5.93 GHz band is rejected.

Ultra wideband tapered slot antenna with band-stop characteristic

In this paper, microstrip-fed slot antennas with suppressed harmonics are proposed. To obtain this operation, conductor lines connected with ground plane are inserted in slot antennas. To verify the validation of the proposed antennas, the equivalent circuit analysis is presented. Also, the miniaturization and bandwidth enhancement of the antenna for various applications are achieved and analyzed through parameter study. From the measured return losses, input impedances, and radiation patterns, it is shown that the proposed antennas offer excellent harmonic suppression characteristic in harmonic bandwidth including the second and third harmonic frequencies.

Hyungrak Kim

Papers

Ultra-wideband tapered slot antenna with band cutoff characteristic

A single-feeding circularly polarized microstrip antenna with the effect of hybrid feeding

A study on the UWB antenna with band-rejection characteristic

Ultra wideband tapered slot antenna with band-stop characteristic

Microstrip-fed slot antennas with suppressed harmonics