K. Usha Kiran

Miniaturized High-Gain UWB Monopole Antenna with Dual Band Rejection Using CSRR

Ultra-wideband technology (UWB) is used for transmitting large amount of data over wide frequency range. There is always a trade-off between gain and bandwidth of micro-strip patch antenna for UWB. It is difficult to obtain wideband and high gain in an antenna simultaneously. In the proposed design, a compact, high-gain ultra-wideband tree-shaped radiating patch antenna with band notch characteristics is designed. The radiating patch is printed on FR4 substrate with permittivity 4.4. Tree-shaped radiating patch and defected ground structure (DGS) provides a wideband over 2.8–11.6 GHz frequency range. For providing stop-band notches in the existing wireless technologies, two complementary split-ring resonators (CSRRs) are used. By etching square complementary split-ring resonator (CSRR) in the feed, a stop-band notch at WLAN (5.1–5.9 GHz) frequency range is obtained, and a single CSRR in the patch provides a notch at WiMAX (3.3–3.6 GHz) frequency range. The antenna has varied positive gain over all the frequencies other than notched bands. Maximum gain of 5 dB at 9 GHz and minimum of 0.4 dB at 4 GHz is obtained. Antenna is simulated using high frequency structure simulator (HFSS) software. The designed antenna is validated by comparing simulated results with measured results.

Study on Gain Enhancement of the Antenna Using Planar Small Metasurface Lens

This paper proposes the analysis of unit cell of different shapes which would be in future used to form a metasurface lens for enhancing the gain. In this paper, various shapes such as rectangular, hexagonal, etc. of the unit cell are designed to operate at about 5 GHz frequency and are analyzed and simulated using HFSS 16.0. The relative permittivity and the relative permeability is calculated and analyzed for the designed unit cell.

Frequency Tuning Method for Small Profile Metamaterial Based on Tri-Ring Resonator

The metamaterials are structures that show the different electromagnetic properties than usual transmission line/medium, such as negative values of permittivity, permeability and refraction. Due to unique behaviour of metamaterial, it gives passband or stopband response for a certain frequencies: a property called resonant. Typical response of metamaterial is narrow band and resonant at particular frequency based on its dimension. A method is proposed in this paper to control or shift the response frequency of tri-ring resonator without altering its dimension.

Conventional DMTL Phase Shifter is Designed Without Meta-material and with Meta-material

Miniaturized antenna and phase shifter are designed for 10 GHz. The antenna is composed of a silicon substrate having high dielectric constant which reduces the size of the antenna. In this design, micro-machining concept is used to reduce the losses by removing some part of the silicon underneath the rectangular patch. DMTL phase shifter is designed and later stacked with meta-material complementary split ring resonator (CSRR) in the transmission line and ground plane of the coplanar waveguide to diminish the effective length of the CPW and increases phase shift, and both the results are discussed in this paper. Single-bit phase shifter for 90° is demonstrated, and the effect of loading is studied.

Study of Electromagnetic Band Gap Structures for antenna application

This paper analyses the Electromagnetic Band Gap Structure that acts as surface wave suppresser. The High impedance characteristics for the design frequency is obtained by two port transmission line method. Application of the Electromagnetic Band Gap Structure for isolation between antennas is carried out. Reducing the size of EBG structure is the main aim of the paper and it is carried out by the use of C shaped slots on every unit cell structure. This design provides satisfactory characteristics for using the antenna in 2.4GHz frequency range. The proposed structure is analyzed using High Frequency Structural Simulator.

Low actuation series switch

This paper mainly concentrate on the mechanical and RF characteristics of RF MEMS series switch. This paper proposes a kind of RF MEMS switch with a special cantilever beam section which will solve the problem of actuation voltage and residual stress. The cantilever beam section having actuation voltage of 5V with stress factor 0.96Mpa. The insertion loss of the switch is 0.1dB and return loss was around 19dB at 20 GHz.