CPW-Fed Stair-Shaped Slot Antennas With Circular Polarization

The design of a microstrip‐fed annular‐ring slot antenna (ARSA) with circular polarization (CP) radiation is initially studied. To obtain CP radiation with broad 3‐dB axial ratio (AR) bandwidth that can cover the WiMAX 2.3 GHz (2305–2320 MHz, 2345–2360 MHz) and WLAN 2.4 GHz (2400–2480 MHz) bands, a novel technique of extending an inverted L‐shaped slot from the bottom section of the annular‐ring is proposed. To suppress the harmonic modes induced by the CP ARSA, the technique of integrating a defected ground structure into the annular‐ring slot is further introduced. From the measured results, 10‐dB impedance bandwidth and 3‐dB AR bandwidth of 44.86 and 9.68% were achieved by the proposed harmonic suppressed CP ARSA. Furthermore, average gain and radiation efficiency of ∼4.7 dBic and 71%, respectively, were also exhibited across the bands of interest. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:337–345, 2015.

Annular-ring slot antenna designs with circular polarization radiation

Sim

Weng

Chang

et al. 2014

Circularly polarized slot antenna array with sequentially rotated feed network for broadband application

Karamzadeh

Virdee

Rafii

et al. 2014

This article presents a novel circularly polarized sequentially rotated slot antenna array (CPSSAA) designed to operate at a frequency of 5.5 GHz. This antenna is suitable for communication applications such as WLAN/WiMAX. Method of feeding is based on sequential rotation with seven quarter-wavelength transformers. In this case, the elements with 200 X impedance could be replaced by other elements with different input impedance. Reducing the elements input impedance, maximum power can be transferred to the elements. Because the lower losses in transmission line occur in presence of lower impedance, the 3 dB axial-ratio bandwidth of the CPSSAA extends to~1.3 GHz. The CPSSAA was designed to operate over the frequency range between 4.5 and 6.4 GHz corresponding to an impedance bandwidth of 34.86% for VSWR < 2. Acceptable agreement between the simulation and measured results validates the proposed design.

CPW-fed C-shaped slot antenna for broadband circularly polarized radiation

Ding

Gao

Tang

et al. 2015

A novel broadband circularly polarized (CP) C-shaped slot antenna fed by a coplanar waveguide is presented. The broadband CP operation can be achieved simply using a C-shaped slot in the ground to produce orthogonal surface currents for left-hand circular polarization. Using the semicircle-shaped radiator patch, wide impedance bandwidth and broad axial-ratio (AR) bandwidth can be obtained simultaneously. The measured results show that the proposed antenna can provide a 10-dB impedance bandwidth of 105% from 2.78 to 8.92 GHz, and a 3-dB AR bandwidth of 70.4% from 2.9 to 6.05 GHz. Finally, an antenna prototype with a reflector for unidirectional pattern applications is also developed. The proposed antenna has broader impedance and CP bandwidths but with a more compact size compared with the previous designs. V C 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:739-746, 2015.