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Design of asymmetrically slotted hexagonal patch antenna for high-gain UWB applications
A compact slot antenna for high-gain ultra wideband applications is presented. The slot is asymmetrically cut in the ground plane and is a combination of two rectangles. A hexagonal patch with two stepped coplanar waveguide-feed is used to excite the slot. The capacitive reactance of the hexagonal patch is neutralized by the inductive reactance created by the asymmetric slot and results into wider
A comparison between GA, PSO, and IWO for shaped beam reflector antennas
This paper presents a comparison between three evolutionary algorithms (EAs) for pattern synthesis of offset reflector antenna fed by a planar array of horn antennas. To perform the optimization process, an elliptical-shaped beam in the U?V plane (U = sin? cos? and V = sin? sin?) is considered as the desired far-field radiation pattern. To attain the appropriate excitation value for array elements
A design of analog VDD generator for passive UHF RFID Tag in 90 nm CMOS
This paper introduces a VDD generator for the ultrahigh frequency (UHF) passive Radio-frequency identification (RFID) tag, consisting of an RF-limiter, an NMOS rectifier, a DC-limiter, and a regulator. The proposed NMOS rectifier utilizes diode-connected native NMOS transistors with ultralow-threshold voltage instead of Schottky diodes. The theoretical equations for predicting the performance of t
Reliability study of a tunable Ka-band SIW-phase shifter based on liquid crystal in LTCC-technology
A tunable substrate-integrated waveguide phase shifter using low-temperature co-fired ceramic (LTCC)-technology is presented in this paper. By changing the effective permittivity in the liquid crystal (LC)-filled waveguide, the differential phase can be tuned continuously. This is achieved by means of an analog signal applied to the electrodes, surrounding the LC. The design allows for precise tun
The accurate comparison (or calibration) of solid-state noise sources made simple
The accurate comparison (or calibration) of conventional solid-state noise sources is often thought to be a difficult process that only specialized laboratories can perform. In this paper, the uncertainties due to the impedance differences between the sources and their on and off states are emphasized and a simple formula is developed that makes them negligible. It requires an isolator being used
A U-matched printed antenna for dual-band WiFi applications
In this paper, a novel and compact center-fed dual-band WiFi printed antenna is presented. This antenna is designed using two different arms which correspond to the oscillation points of the dual band, and uses parasitic capacitance and U-shaped microstrip line to match and control the necessary bandwidth. The measured frequency bandwidth of this antenna is 2.3?2.61 GHz (310 MHz, 12.7%) at 2 GHz,
Synthesis of thinned planar antenna arrays using teaching?learning-based optimization
In this paper, the design of thinned planar antenna arrays of isotropic radiators with optimum side lobe level reduction is studied. The teaching?learning-based optimization (TLBO) method, a newly proposed global evolutionary optimization method, is used to determine an optimum set of turned-ON elements of thinned planar antenna arrays that provides a radiation pattern with optimum side lobe level
Substrate-perforated and compact ultra-wideband antenna with WLAN band rejection
This paper presents a designed notched band ultra-wideband (UWB) printed antenna using coplanar waveguide-fed configuration. Simple technique of perforating the substrate and modifying the ground plane and radiator patch was used to achieve UWB for the designed antenna at smaller structure. Narrow arch-shaped slot was introduced to the patch of the proposed antenna to obtain the band rejection fun
Mechanical nanogap switch for low-power on-board electronics
This paper presents the design fabrication and measurement of a nanogap radio frequency microelectromechanical system (RF MEMS) metal-contact switch. The prosed device generates a relatively high contact force with a low actuation voltage using a dielectric layer between the actuation electrode and the moveable beam. The actuation voltage is decreased with good reliability of the device by scaling
MMIC-based asymmetric Doherty power amplifier for small cells applications
We present the results obtained on a multi-mode multi-band 20 W Monolithic Microwave Integrated Circuit (MMIC) power amplifier. The proposed two-stage circuit is based on the silicon Laterally Diffused Metal Oxide Semiconductor (LDMOS) technology. Thanks to dedicated design techniques, it can cover the Digital Cellular Service (DCS), Personal Communications Service (PCS), and UMTS bands (ranging f