Log-periodic Toothed Antenna Research Articles

Four-Arm Log-Periodic Toothed Antenna With Hybrid Reflector Composed of Inhomogeneous Metamatarial Elements for Electronic Support Measures

Four-Arm Log-Periodic Toothed Antenna With Hybrid Reflector Composed of Inhomogeneous Metamatarial Elements for Electronic Support Measures

Toothed log periodic graphene-based antenna design for THz applications

This paper proposes a graphene-based toothed log-periodic antenna for the THz frequency region (0.1–10) THz applications. By adjusting the applied DC voltage on the graphene, the antenna's properties, such as bandwidth, radiation pattern operational frequency ranges have been shifted. The chemical potential, surface conductivity, and surface impedance of the graphene are affected by changing applied DC voltage and hence a reconfigurable antenna has been resulting. The suggested antenna's radiating element is from a graphene material and has log-periodic shape, with 50 ohm feed line placed on the grounded silicon dioxide substrate, 1 µm-thick layers of silicon crystalline and alumina on top of the substrate. The antenna is simulated by the computer simulation technology (CST) 2020 software program. The resultant bandwidth (7-10) TH has a return loss of less than -10 when the chemical potential of graphene is 1eV.

Miniaturized Four-Arm Log-Periodic Toothed Antenna With Wide Bandwidth

An improved method of wideband performance is demonstrated by being applied to a miniaturized four-arm log-periodic toothed antenna with an integrated balun. The required minimum length of the integrated balun is reduced through the input impedance reduction structure on thin dielectrics with a low relative dielectric constant. In addition, destructive currents arising from the combination of the antenna structure and miniaturization structure are solved by modeling them as an equivalent circuit structure from an impedance perspective. The proposed antenna represents a voltage standing wave ratio of less than 2:1 in the 1.25&#x2013;18 GHz bandwidth range and has a realization gain of more than 2 dBi in the overall operating band with a diameter of 0.325 <inline-formula><tex-math notation="LaTeX">$\mathbf{\lambda}_{\mathbf {L}}$</tex-math></inline-formula>.

UWB Single Port Log Periodic Toothed Terahertz Antenna Design Based on Graphene Artificial Magnetic Conductor

In this work, a single port exponential tapered toothed log periodic antenna based on graphene artificial magnetic conductor (AMC) is suggested for ultra-wideband (1–10) THz operation. The resonance frequency of the proposed antenna can be tuned by changing the connected DC voltage which leads to variation in the chemical potential of the graphene.The radiating toothed log periodic antenna consists of gold patch placed on 25x25 graphene patches which act as an AMC surface unit. Exponential taper is used to satisfy impedance matching between the antenna and the feeder over the frequency range. The simulation results reveal that 90% of frequency range satisfies when the chemical potential is1eV.

Dielectric-loaded trapezoidal toothed log-periodic antenna

In this article, dielectric-loaded metal trapezoidal toothed log-periodic antenna (TTLPA) is described. The dielectric material, Rogers RT/duroid 6010 (er = 10.2, tan δ = 0.0023) of thickness = 5 mm and of same shape as TTLPA is placed on top of conventional metal TTLPA which provides enhanced bandwidth and/or miniaturizes its aperture size without degradation in gain. The dielectric loading increases the effective length of antenna, and therefore, extends its operating frequency towards lower frequency side which miniaturizes aperture cross-section of antenna with slight increase in its thickness. The simulated input and radiation characteristics of TTLPA without and with dielectric loading are compared. The comparative studies show that the proposed antenna is 38.78% smaller in respect of aperture cross-section as compared with conventional antenna having almost identical bandwidth of 8.6 GHz (2.2–10.8 GHz) and gain variation over the range 1.5–6.1 dBi. The proposed antenna of aperture size 48.9 × 48.9 mm2 provides −10 dB reflection coefficient bandwidth of 8.6 GHz (2.2–10.8 GHz) and gain variation in the range 1.3–5.7 dBi whereas the conventional antenna of same aperture size achieves somewhat reduced bandwidth of 7.6 GHz (3.2–10.8 GHz) and gain variation in the range 1.6–5.0 dBi over the operating frequency range.

BANDWIDTH ENHANCEMENT OF UWB DUAL-POLARIZED ANTENNAS

In this paper, we discuss the impedance and radiation properties of planar UWB (any ultra wide frequency band) dual-polarized antennas. While their performance is usually de¯ned using the impedance bandwidth, some applications require pattern stability over broad frequency bands. An analysis of the behaviour of three UWB dual-polarized antennas (Bowtie Antenna, Toothed Log- Periodic Antenna and Sinuous Antenna) showed interesting conclusions in terms of impedance matching bandwidth and radiation pattern steadiness. Starting from there, we then developped a method that consists in meandering the original structure. This method allows for miniaturization as well as radiation bandwidth enhancement. As a ¯nal result, an electrically small antenna with an impedance bandwidth of more than a decade and a steady radiation pattern over it has been developped.

InP-Based Planar-Antenna-Integrated Schottky-Barrier Diode for Millimeter- and Sub-Millimeter-Wave Detection

An InP-based Schottky-barrier diode (SBD) is monolithically integrated with a wideband log-periodic toothed antenna for detecting millimeter- and sub-millimeter-waves at frequencies of up to the terahertz (THz) range. A module with a quasi-optical collimation lens fabricated for practical use exhibits sensitivities of 1000 V/W at 300 GHz and 125 V/W at 1.2 THz with good linearity. Near-distance wireless transmission of 5 Gbit/s data with a 240 GHz carrier is also examined using the fabricated SBD module.

Photonic generation of continuous THz wave using uni-traveling-carrier photodiode

A uni-traveling-carrier photodiode (UTC-PD) is monolithically integrated with a wideband log-periodic toothed antenna for generating millimeter and submillimeter waves at frequencies of up to terahertz range. A module with a quasi-optical output port fabricated for practical use operates up to 1.5 THz and generates an output power of 2.3 /spl mu/W at 1.04 THz with good linearity. The output power level and the operation frequency are records for wideband PD modules operating at 1.55 /spl mu/m. An investigation of the operational characteristics of the UTC-PD reveals that the effective use of the electron-velocity overshoot in the junction depletion layer is important for maximizing the output power in the terahertz range.

New results for NbN phonon-cooled hot electron bolometric mixers above 1 THz

NbN Hot Electron Bolometric (HEB) mixers have produced promising results in terms of DSB receiver noise temperature (2800 K at 1.56 THz). The LO source for these mixers is a gas laser pumped by a CO/sub 2/ laser and the device is quasi-optically coupled through an extended hemispherical lens and a self-complementary log-periodic toothed antenna. NbN HEBs do not require submicron dimensions, can be operated comfortably at 4.2 K or higher, and require LO power of about 100-500 nW. IF noise bandwidths of 5 GHz or greater have been demonstrated. The DC bias point is also not affected by thermal radiation at 300 K. Receiver noise temperatures below 1 THz are typically 450-600 K and are expected to gradually approach these levels above 1 THz as well. NbN HEB mixers thus are rapidly approaching the type of performance required of a rugged practical receiver for astronomy and remote sensing in the THz region.