Design of Thin and Wideband Microwave Absorbers Using General Closed-Form Solutions

A new design method for RLC reactive absorbers is presented. This method is based on closed-form solutions to help realize the widest absorption bandwidth for an arbitrarily specified thickness. The solutions for the RLC values of the reactive screen are derived using an equivalent circuit in which the thickness of the substrate used, the permittivity and tangential loss of the substrate, and the frequency are all considered. A perfect match and maximum bandwidth at a design frequency can be achieved with the proposed method. Various aspects of the absorber characteristics, depending on the thickness and loss of the substrate, are analyzed using the presented solutions and electromagnetic (EM) simulations. To validate the proposed design method, an X-band microwave absorber with a crossed-dipole structure patterned on a silver nanowire resistive film is designed, fabricated, and measured. The substrate electrical thickness of the absorber is 70° at 10 GHz, with a permittivity of 2.2. The 90% absorption bandwidth is 8 GHz in the frequency range of 8.2–16.2 GHz. The measured absorption agrees well with the results obtained using circuit and EM simulations.

25GHz - 40GHz Circularly Phase Array Microstrip Patch Antenna for Millimeter Wave Communication

Millimeter wave technology will enable to provide high data rate. It is also expected to provide continuous good quality, low latency video. For high-resolution video, wireless communication will require huge bandwidth. The present 4G spectrum will be unable to meet the demand of each mobile user. To solve bandwidth shortage millimeter wave technology is consider. In this paper present a circularly phase array designed. It is operating in the 25GHz to 40GHz. To enhance bandwidth the array used edge couple parasitic patch arrangement which provides dual resonance. The array is designed in circular phase array with the rotational feeding line. The designed used polyflon CuFlon(tm) low dielectric constant, Ɛr = 2.1 and tangential loss, δ = 0.00045 with height h = 1.6mm. The designed achieved 8.41dB gain. The array achieved good return loss, S11 bandwidth i.e. -11.83dB ≤ S11 ≤ -37.8dB (25GHz to 40GHz) and voltage standing wave ratio, VSWR ≤ 1.7 (25GHz to 40GHz).