Wideband constant beamwidth coplanar waveguide‐fed slot antennas using metallic strip loadings and a widened tuning stub with shaped reflectors

Sectored antennas with wideband operation for wireless communication systems are presented. The proposed configurations are based on a coplanar waveguide fed slot antenna using metallic strip loadings and a widened tuning stub above various reflector shapes. By shaping the reflector, noticeable enhancements in both unidirectional radiation pattern and beamwidth can be achieved while maintaining the simple fabrication and installation. Based on the results obtained, three sector antennas covering 72°, 90°, and 120° beamwidths suitable for five, four, and three sectors, respectively, have been proposed and designed. The simple structural configurations, low cost, and ease of half power beamwidth control of the proposed antennas make the design very attractive for practical implementation. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Compact wideband microstrip thinned array antenna using EBG superstrate

A compact wideband microstrip array antenna with EBG superstrate is presented. We compare and summarize the results for the impedance bandwidth and gain characteristics of three different antenna prototypes, namely two conventional 2 × 2 arrays with EBG superstrate and 2 × 2 array of multiple resonator patches with EBG superstrate. The designed antenna has a moderate gain of over 8.5 dBi and a wideband impedance bandwidth of over 20%, which covers the required bandwidth of the WLAN (2.4-2.484 GHz) and WiMAX (2.3-2.5 GHz) systems. The EBG superstrate is also utilized to achieve a thin antenna with a cavity height of λ₀/16 at the center frequency of 2.45 GHz. The proposed antenna is low-cost and low-profile, having overall dimension of 0.9 λ₀ × 0.9 λ₀ × 0.081 λ₀ (110 mm × 110 mm × 9.9 mm).     

Broadband bandpass filters using slotted resonators fed by interdigital coupled lines for improved upper stopband performances

This paper proposes new broadband microstrip bandpass filters based on slotted linear tapered-line resonator (SLTR) and slotted step impedance resonator (SSIR) structures for size reduction and improved stopband performances. A comprehensive treatment of slotted resonators and both ends of the resonator with interdigital coupled lines is described. The design concept is demonstrated by two filter examples including one with an SLTR and another one with an SSIR. These filters have not only compact size but also a wider upper stopband resulting from resonator bandstop characteristics. The simulated and experimental results of stopband performances are better than 15 dB for a frequency range up to 25 GHz.     

CPW-fed mirrored-L monopole antenna with distinct triple bands for WiFi and WiMAX applications

By coupling a stub-loaded open-loop resonator onto the back of a CPW-fed mirrored-L monopole, a novel triple-band planar antenna has been achieved and is presented. The proposed antenna features a compact structure with reasonable gains. The measured bandwidths for the distinct triple-band are 2.27-2.87-GHz, 3.4-4.15-GHz and 5.11-6.7-GHz. Omnidirectional radiation patterns for the three bands are observed. Simulations are confirmed by the experimental results, which ensure that the proposed antenna is well suited for WiFi and WiMAX applications.