GHz Applications Research Articles

Growth of pure and BFO doped KCl crystals by Czochralski technique and fabrication of microstrip patch antenna for GHz applications

Large sized pure and 0.1 mol% BiFeO3 (BFO) doped KCl single crystals were grown by Czochralski technique. Structural parameters were confirmed by powder XRD and single crystal XRD. EDX analysis was used to determine the elemental composition of BFO and KCl crystal. Photoluminescence confirmed that BFO acts as defect quenching agent for KCl single crystal which improved its optical transparency. Doping of BFO in KCl single crystal increased its hardness as measured by a Vicker’s microhardness test. The effect of BFO on dielectric constant and dielectric loss of KCl crystal, at various temperature and frequencies was studied. The low dielectric constant viz. 4.5 and 5.8 for pure and BFO doped KCl was helpful in designing and fabricating patch antenna in GHz frequency. As a result of BFO doping, the resonant frequency of microstrip patch antenna can be tuned at 5.40 GHz from 6.01 GHz for the KCl single crystal.

60 GHz Substrate-Integrated-Waveguide-Fed Patch Antenna Array With Quadri-Polarization

This communication presents a new design of a quadri-polarization-agile aperture-coupled patch antenna array for 60 GHz applications. Four polarization states, namely, vertical linear polarization, horizontal linear polarization, left-hand circular polarization (LHCP), and right-hand circular polarization (RHCP) can be flexibly reconfigured by dynamically switching the excitation of the corresponding port. More importantly, as the LP and CP radiations are achieved by using differential feeding and sequential-rotation feeding, respectively, the array exhibits wide impedance and axial ratio (AR) bandwidths, high polarization purity as well as symmetrical pattern with the main beam fixed at boresight. The −10 dB impedance bandwidths are better than 11.6% (57–64 GHz) for the four polarization states. The measured AR bandwidths are from 58 to more than 64 GHz for both the LHCP and RHCP. The good radiation performance together with the quadri-polarization-agile capability of this new array, as demonstrated in the communication, underlines its suitability for the future 5G communication systems, especially in a multipath propagation environment.

A CNTFET universal mixed‐mode biquad active filter in subthreshold region

This paper presents a new low-voltage and low-power mixed-mode universal active filter, using only 12 carbon nanotube field effect transistors (CNTFETs) and 2 grounded capacitors to improve the noise performance of the proposed circuit. Due to the use of subthreshold transistors biased at ±0.2 V supply voltage, the power consumption of the proposed multi input-single output (MISO) filter is only 850 nW at 19 MHz center frequency. On the other hand, relaxing from any matching components, the center frequency and quality factor of the proposed filter can be tuned electronically with low sensitivity to the values of the active and passive elements. Furthermore, the active chip area of the proposed filter is significantly reduced to 0.047 μm2, in 32 nm CNTFET technology. Therefore, as the HSPICE simulation results show, the input referred noise values at 19 MHz are reduced to 15.5 nV/ Hz and 185 fA / Hz in voltage and current modes, respectively. It is also shown that, by changing the number of nanotubes in the CNTFET structure, a very good power-frequency trade-off can be achieved for low-power GHz applications.

Dual-polarized lens antenna based on multimode metasurfaces**Project supported by the Open Research Program of the State Key Laboratory of Millimeter Waves, China (Grant No. K201926), the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China, and the Nanjing University of Posts and Telecommunications Scientific Foundation, China (Grant No. NY215137).

We propose a dual-polarized lens antenna system based on isotropic metasurfaces for 12 GHz applications. The metasurface lens is composed of subwavelength unit cells (0.24λ0) with metallic strips etched on the top and bottom sides of the unit cell, and a cross-slots metallic layer in the middle that serves as the ground. The multimode resonance in the unit cell can realize a large phase shift (covering 0°–360°), and the total transmission efficiency of the lens is above 80%. The feed antenna at the focal point of the lens is a broadband dual-polarized microstrip antenna. Both the simulated and the measured results demonstrate that the dual-polarized lens antenna system can realize a gain of more than 16.1 dB, and an input port isolation of more than 25.0 dB.

Coplanar waveguide fed dual‐band dual‐sense circular polarized square slot antenna

A novel design of a dual-band dual-sense circularly polarized square slot antenna with two rectangular shaped parasitic patches etched on a single substrate for 1.74/2.82 GHz applications is presented. A coplanar waveguide (CPW) fed line with two horizontal branches of different lengths is used, which produce two different frequencies bands. However, good circular polarization (CP) performance is achieved by adjusting the size of the parasitic patches. The two branches of feed line can excite dual-band dual-sense circular polarized wave. The antenna generates right hand circular polarization (RHCP) and left hand circular polarization (LHCP) radiation at 1.74 and 2.82 GHz, respectively. Lower band is obtained due to 90° phase difference between currents in the two orthogonal branches of the feed line. The lower band of CP is controlled by the size of parasitic patch/element (PE2) and the upper band of CP is controlled by length of right-sided horizontal branch of feed line. The key parameters of the design are investigated to show how to obtain dual CP with impedance matching.

Circularly Polarized Substrate-Integrated Cylindrical Dielectric Resonator Antenna Array for 60 GHz Applications

A 60 GHz circularly polarized (CP) substrate-integrated cylindrical dielectric resonator antenna (DRA) and its 2 × 2 array are studied. Each DRA element is excited in its HEM11δ mode by an aperture-coupled source. To obtain CP fields, each element is top-loaded by a patch, which has a pair of slits. For the array, a sequential-rotation feeding network is used to widen the bandwidth of the axial ratio. Reasonable agreement between the measured and simulated results is observed. It is found that the array can be used for the 60 GHz band (57–64 GHz), with a peak measured antenna gain of 11.43 dBic.

Co-planar Truncated Corner Patch Antenna with Fishbone-Shaped Slot Structure

This work proposed the co-planar truncated rectangular antenna with fishbone-shaped slot structure at the patch for GSM 1.8 GHz and WLAN 5.2 GHz applications. This work provides in six different develop, including a stage from Design A to Design F. Firstly, a basic rectangular patch antenna is done for Design A while the second stage is rectangular patch with cut-out truncated shaped at the below part for Design B. Then, it followed by the added co-planar effect for Design C, added fishbone slot structure for Design D, mirror effect of truncated patch for Design E and lastly cut-off triangular truncated corner at the patch for Design F. The performance of proposed antenna of Design F at resonant frequencies of 1.8 GHz and 5.2 GHz is – 25.207 dB and – 16.625 dB, respectively.

Low Loss Transmission Circular Polarizer for KU Band Application

Low loss transmission circular polarizer is proposed for Ku band applications. The designed structure consists of two closely cross metallic strips which are based on FSS for 15.25 GHz and 15.28 GHz applications. The right hand circular polarization (RHCP) and left handed circular polarization (LHCP) are obtained at 15.25 GHz and at 15.28 GHz. The transmission loss through polarizer is important issue for high frequency applications. Due to transmission loss, new techniques are required to reduce the transmission loss of transmitted wave and achieve perfect circular polarization. Meanwhile, low loss transmission has been achieved by using dual layer of strips to obtain perfect circular polarization at certain mentioned resonant frequencies. Theoretically, it is found that the outgoing waves through polarizer are perfect circular polarization at the distinct frequency ranges.

Labyrinth double split open loop resonator based bandpass filter design for S, C and X-band application

Nested circular shaped Labyrinth double split open loop resonators (OLRs) are introduced in this article to design a triple bandpass filter for 3.01 GHz, 7.39 GHz and 12.88 GHz applications. A Rogers RT-5880 is used as a substrate to design the proposed passband filter which has a succinct structure where the attainment of the resonator is explored both integrally and experimentally. The same structure is designed on both sides of the substrate and an analysis is made on the current distribution. Based on the proposed resonator, a bandpass filter is designed and fabricated to justify the perception focusing on 3.01 GHz, 7.39 GHz and 12.88 GHz. It has also been observed by the Nicolson–Ross–Weir approach at the filtering frequencies. The effective electromagnetic parameters retrieved from the simulation of the S-parameters imply that the OLR metamaterial filter shows negative refraction bands. Having an auspicious design and double negative characteristics, this structure is suitable for triple passband filters, particularly for S, C and X-band applications.

A CMOS 6–10 GHz impulse radio UWB transmitter based on gated oscillator with switching pulse shaper

In an impulse radio ultra-wideband (IR-UWB) system for low-power location-aware sensor networks, the output pulses must meet the FCC spectral emission mask. In addition, to increase battery life, the IR-UWB transmitter must be energy efficient. In this paper, a CMOS ultra-wideband (UWB) transmitter designed using a 0.11-μm process is presented for 6–10 GHz applications. To reduce energy consumption, the transmitter adopts a gated voltage-controlled oscillator (VCO) that directly drives 50 Ω output impedance. A gated VCO that uses a trapezoidal pulse for on/off gating of the tail current source satisfies the spectrum mask without requiring an additional pulse shaping filter. The active energy consumption is 13.4 pJ/pulse at a pulse repeating frequency (PRF) of 40 MHz. The side-lobe rejection performance is more than 30 dB.

Design, analysis and fabrication of compact dual band uniplanar meandered ACS fed antenna for 2.5/5 GHz applications

In this research, a compact meandered shape design of printed antenna with dual operating frequencies for 2.5/5 GHz applications is presented and experimentally investigated. The proposed multi band antenna is feed with asymmetric coplanar strip (ACS) and has a size of 10 mm × 19 mm. The L and meandered elements acts as a radiating elements that produces operating frequencies from 2.5 to 2.7 GHz and from 4.6 to 6.1 GHz with 200 and 1500 MHz impedance bandwidths respectively. Also, simulation study of feeding the proposed structure with microstrip concept is carried out and similar performance results are found in both ACS and microstrip techniques. The performance of the dual band antenna in terms of return loss, design evolution, radiation patterns and peak gain is studied.

60 GHz Wideband High-Gain Circularly Polarized Antenna Array With Substrate Integrated Cavity Excitation

This letter presents a new wideband high-gain circularly polarized (CP) substrate integrated cavity excited antenna array for the 60 GHz applications. First, a 2 × 2-element CP array is proposed with an aperture-coupled two-arm spiral antenna as its radiating element, which can exhibit good CP radiation performance. Instead of the conventional lossy and complicated feed network, a simple but efficient excitation structure based on higher-order-mode (TE340) cavity resonance is used to feed the array. The higher-order-mode cavity feeds all of the radiating elements in the same phase and magnitude, and the resonant mode is excited by a single slot aperture. Then, the proposed 2 × 2-element CP array is used as subarray to implement a sequential-rotationally fed 4 × 4-element CP array. Measured results show that the array has a wide axial-ratio bandwidth of more than 18.8% (53–64 GHz) with a peak gain reaching 20 dBic occurring at 61 GHz. The radiation patterns of the array are generally symmetrical with its main beam fixed at boresight.

Design of Frequency Reconfigurable Antenna Working in Ka Band

In this study of reconfigurable antenna technology is presented. The important applications that can be used with the reconfiguring techniques, studying the history of this technology in brief literature survey is examined. A detailed information on the technique background information are specified, reviewing the different reconfigurable components, which can be used in an antenna to adjust its functionality and construction. These reconfigurable antenna techniques are divided with a different classification method and explain whichever established on the physical changes of the reconfigurable antenna radiating parts, or on the integration of varactors, photoconductive components, PIN diodes, or on the function of materials etc. the designed covers the Fixed-Satellite (space-to-Earth), Mobile satellite 19.7GHz to 20.2GHz applications.

High‐gain broadside dipole planar AMC antenna for 60 GHz applications

A novel 60 GHz high-gain planar artificial magnetic conductor (AMC) antenna is proposed. The prototype of the antenna is a dipole structure with a broadband input impedance match. Parasitic patches and a novel AMC plane are successively used to enhance its broadside gain. The antenna has a compact size of 7.5 mm × 8 mm, including the modified AMC plane. Simulated and measured results both show the antenna has good properties of return losses better than 10 dB, stable peak gains up to 10.9 dBi and favourable radiation patterns from 57 to 64 GHz, which all denote that it is fit for 60 GHz wireless portable communication systems.

Dual Circular-Polarized SIW-Fed High-Gain Scalable Antenna Array for 60 GHz Applications

In this paper, a dual circularly polarized high-gain scalable antenna array is proposed for the 60 GHz applications. The array consists of cross-slot-coupled cavity-backed square patch antenna elements fed by a novel substrate-integrated waveguide network. In our design, the two polarizations share the common radiating element and feed network so that they exhibit similar performance in terms of bandwidth, gain, and radiation patterns for both polarizations. An $8 \times 8$ element array is designed to demonstrate its function, and the simulated data exhibit an overlapped bandwidth (SWR < 2, 3 dB down gain bandwidth and AR < 3 dB) of approximately 23%, a gain up to 25.8 dBic for both ports, and a port-to-Port isolation larger than 14 dB. Good unidirectional and symmetrical radiation patterns are observed. A prototype is fabricated, and the measured results agree with the simulated ones with acceptable disparities. The reported structure is built by the conventional printed circuit board technology which is cost effective. With these advantages, the proposed scalable antenna design is a good candidate for millimeter-wave wireless communications.

Design and Implementation of 4 Elements Circular Patch Antenna with High Gain for 3.0 GHz Applications

Design and Implementation of 4 Elements Circular Patch Antenna with High Gain for 3.0 GHz Applications

Novel double fractal patches structure Antenna-in-Package based on LTCC technology for 2.4 GHz applications

A novel Antenna-in-Package with small size and low profile is designed based on Low Temperature Co-fired Ceramic technology. In order to realize miniaturization and broadband in antenna part, a novel structure using double fractal antennas and air cavities is applied. A packaging cavity is designed for integrated with usable components and IC chips. The antenna operates at a center frequency of 2.4 GHz and the bandwidth is about 200 MHz. Its maximum gain is 5.6 dBi, and radiation efficiency is above 90% across the frequency passband. By adjusting the dimension parameters, a tradeoff between height and area can be made with its performance parameters constant, therefore the proposed Antenna-in-Package can easily adapt to different processes and performance.

A quad‐band dual‐polarized monopole antenna for GNSS/UMTS/WLAN/WiMAX applications

AbstractA quad‐band dual‐polarized monopole with asymmetrical microstrip feed line is proposed in this article. The proposed antenna exhibits a linearly polarized behavior in three operating bands for UMTS, WLAN 2.4 GHz, and WiMAX 3.5 GHz applications while a circularly polarized nature in the lowermost band for the GPS/GLONASS. The multiband operation is achieved because of λ/4 mode of resonances of three different monopole lengths and 3λ/4 mode of longer monopole. The 3λ/4 mode of larger monopole is controlled by using an L‐Shaped stub to make it useful for WiMAX application (3.5 GHz). The circular polarization for GPS (band‐L1, 1575 MHz) is achieved by using an L‐shaped slit with the ground plane which leads to generation of magnetic current orthogonal to the longest monopole current corresponding to the lowermost resonance frequency. The proposed antenna exhibits impedance bandwidths of 11.22%, 7.9%, 6.84%, and 4.26% at the resonant frequencies of 1.5, 2.02, 2.46, and 3.51 GHz, respectively. The axial ratio bandwidth corresponding to the GPS band is 2.5%. The proposed antenna has dual sense circular polarization (LHCP in θ = 0° and RHCP in θ = 180°) and bi‐directional radiation patterns at GPS/GLONASS band along with stable gain and good efficiency in all the operating bands.

Design and Analysis of a Micromachined LC Low Pass Filter For 2.4GHz Application

This paper reports design and analysis of a passive low pass filter with cut-off frequency of 2.4 GHz using MEMS (Micro Electro-Mechanical Systems) technology. The passive components such as suspended spiral inductors and metal-insulator-metal (MIM) capacitor are arranged in T network form to implement LC low pass filter design. This design employs a simple approach of suspension thereby reducing parasitic losses to eliminate the performance degrading effects caused by integrating an off-chip inductor in the filter circuit proposed to be developed on a low cost silicon substrate using RF-MEMS components. The filter occupies only 2.1 mm x 0.66 mm die area and is designed using micro-strip transmission line placed on a silicon substrate. The design is implemented in High Frequency Structural Simulator (HFSS) software and fabrication flow is proposed for its implementation. The simulated results show that the design has an insertion loss of -4.98 dB and return loss of -2.60dB.

60 GHz Dual-Circularly Polarized Planar Aperture Antenna and Array

This communication presents new designs of dual-circularly polarized (CP) planar aperture antenna and array for 60 GHz applications. First, a four-port planar aperture antenna with its feeding network is developed that exhibits wide impedance bandwidth, dual-CP radiation as well as high gain. Then, based on the proposed antenna, a new scheme of building a dual-CP array is proposed. With this new scheme that combines the power splitting network and series feeding method, four sequentially fed antenna elements are successfully combined to form a CP radiation array. The experimental results show that the −10 dB impedance bandwidths of the antenna and the array are more than 18.2% (55–66 GHz). While the 3 dB axial ratio bandwidths are from 54.2 to 64.3 GHz (17.2%) for the antenna and from 54.8 to 65 GHz (17%) for the array. The maximum gains achieved are 13.7 and 17.85 dBic for the antenna and array, respectively.