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A novel design of a high-frequency multiband with a circular polarisation antenna based on a four-patch antenna system consolidated with an Archimedean spiral antenna for CubeSat applications. The geometry and size are compatible with the CubeSat standard structure dimensions of 10 x 10 cm². The antenna consists of a spiral antenna in the middle of four patch antennas surrounding it; the first antenna structure consists of two sets of two orthogonal identical patch antennas with a 90° phase shift to cover the band from 1.55 to 1.94 GHz at L-band, 2, 2.1, and 2.3 GHz at S-band, the second antenna is an Archimedean spiral antenna to cover all C-bands, all X-bands, all Ku-bands, all K-bands, and from 26 to 29 GHz at Ka-band. The measured results show that the reflection coefficients (S11) and (S22) achieve < -10 dB and the axial ratio achieves <3 dB, with a reference impedance of 50 Ω. The simulated and the measured results give a better agreement. [ABSTRACT FROM AUTHOR]

In this paper, an 18 GHz voltage-controlled oscillator (VCO) with improved phase noise (PN) and smaller size is proposed. The filter consists of an open stub resonator and an integrated spiral Defective Ground Structure (DGS) resonator. The proposed oscillator is designed in the 0.13-µm SiGe BiCMOS technology. The differential cross-coupled VCO uses a bandpass filter. In this work, the conventional large-size coil is replaced by a resonator based on our proposed open stub resonator and defected ground structure (DGS) where the filter is equivalent to the large coil and the associated capacitors. The use of the filter results in a great reduction of VCO size, low losses, and low power consumption, hence an enhancement in the quality factor. The integrated spiral DGS is etched on the third metal layer (M3) below an open stub meander line onthe top metal layer (TM2) of the 0.13-µm top metal two (TM2) BiCMOS technology. The proposed VCO has a small die area of 0.089 mm2 and has FoMA of 188.8 dB and a power consumption is 13.38 mw. The simulated carrier frequency and phase noise are 18-GHz and −123.59 dBc/Hz (−103.7 dBc/Hz) at 10-MHz (1 MHz) offset frequency, respectively, which results in a figure of merit of 177.37 dB. [ABSTRACT FROM AUTHOR]

This manuscript presents the design of a 76- 82 receiver front-end for W-band automotive radar in a 130 nm SiGe technology. The front-end consists of a low noise amplifier (LNA), broadband passive balun and a double-balanced mixer integrated with buffer. The proposed LNA employs a single-stage cascode topology. The post-layout simulation results show that the LNA has a power gain and noise figure (NF) of 14.7 dB and 5 dB, respectively. While the downconverter mixer provides 18.3 dB gain and 9.3 dB NF. Furthermore, the broadband Marchand Balun achieves amplitude and phase imbalance better than 0.3 dB and 8 degrees, respectively. Additionally, the total DC power consumption from the LNA, mixer, and buffer are 35 mW, 5.1 mW, 150 mW, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a new super-resolution and highly stable DOA estimation technique of coherent sources is introduced. Furthermore, the proposed technique is applied to the data collected from the AWR1243 mm-wave 76-81 GHz frequency modulated continuous wave (FMCW) radar to estimate the DOAs of real targets. A virtual antenna array is proposed to increase the array aperture size and the dimension of the data covariance matrix which effectively helps in de-correlating the received signals and in increasing the number of detectable sources and hence improving the detection resolution. Moreover, a significant improvement in the DOA estimation capability is achieved by handling the frequency domain of the received signals instead of their time-domain representations. That is because the signal to noise ratio (SNR) is increased by a multiplication factor when it is transformed using FFT which acts as a filter for the noise. The simulation results proved the superiority of the proposed technique compared to the state of the arts in this field, especially at low SNR that approaches -35 dB. [ABSTRACT FROM AUTHOR]

Distributed beamforming (DBF) is an efficient technique for reliable communications in wireless sensor networks (WSNs). In DBF based networks, the randomly distributed nodes cooperate to form a randomly distributed antenna array (RAA) which has a main beam directed towards the intended receiver. Due to the nodes randomness, the DBF results in poor pattern characteristics such as high side lobe level (SLL) and pattern asymmetry around the main beam sides. In this paper, a fast deterministic algorithm for SLL reduction of open loop distributed antenna arrays is introduced. Unlike the existing state of the art optimization techniques for SLL reduction, the proposed algorithm provides a fast deterministic solution for energy transmission or the weight of each node without changing its location. Consequently, the exhaustive search burden of the optimization based techniques for the optimum weights is avoided. The simulation results reveal that the proposed algorithm has superior performance to the optimization techniques in terms of execution time, synthesized SLL, and half power beamwidth (HPBW). [ABSTRACT FROM AUTHOR]

This paper introduces a novel MIMO UWB antenna with dual notches. The proposed antenna is based on Quasi Self Complementary (QSC) method to give wide impedance bandwidth from 2.4GHz to more than 12 GHz. The proposed antenna consists of a semi-elliptical patch that is fed by a tapered microstrip line. The antenna is designed on an FR-4 substrate with compact size 20mm × 15mm × 1.5mm. The dual notched bands are achieved by using a square ring printed on the bottom of the substrate to reject WiMAX at 3.6 GHz. Also, a C-shaped slot is etched in the radiating patch to reject interference with the WLAN band at 5.8 GHz. In the proposed MIMO antenna, the isolation reduction is achieved utilizing diversity technique to minimize the mutual coupling between the antennas. The isolation between MIMO elements is more than 20 dB. The envelope correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), furthermore, channel capacity loss (CCL) are measured and calculated. The proposed antenna is designed, simulated, and measured. A good agreement is shown between the experimental and simulated results. [ABSTRACT FROM AUTHOR]

In this paper, a new configuration of dual-band, dual-polarized microstrip antenna applicable to mobile base stations is proposed. The concept behind the new design is the use of an artificial magnetic conductor (AMC) structure that operates in the required two bands beneath a radiating diamond shaped slot. The choice of the diamond-shaped slot is due to its support of an infinite number of resonant modes where the dimensions of the diamond shape have more degree of freedom that controls the excited modes when compared to the rectangular slot. The proposed antenna works over the 870–960 MHz (GSM850/GSM900) band and the 1710–2170 MHz (DCS1800/PCS1900/UMTS2100) bands for mobile communication systems. The antenna is suitable for transmitting and receiving mobile signals since it has two ports of orthogonal polarization. The antenna is fabricated on a combination of FR4 dielectric substrate and foam layers in order to achieve low cost. The proposed antenna yields high isolation between its two ports not exceeding −30 dB and a front-to-back ratio exceeding 15 dB. The average antenna gains are about 6.6 dBi at the GSM850/GSM900, 7.1 dBi at the DCS1800/PCS1900, and 6.8 dBi at the UMTS2100 bands. The theory of radiation is proved analytically and verified by comparing its results with some simulated results. Finally, a good agreement between the simulated and measured results is noticed. [ABSTRACT FROM PUBLISHER]

With the vast emergence of new mobile applications, multiband operation in a compact size is mandatory for market penetration. In this paper, a new mobile handset antenna suitable for both mobile and wireless LAN services is presented. The antenna operates for most of the mobile applications such as the GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands, especially the low frequency LTE 700 band at -10 dB. The antenna also supports the WIMAX, WLAN, and the ISM bands. The antenna not only has a compact size, but also supports a low SAR radiation at all the operating frequencies. The antenna consists of two concentric open rings that act as quarter wavelength monopoles. The inner ring radiates at 900MHz, while the outer ring radiates at 700MHz. The inner ring works as a monopole radiator as well as a slot radiator fed by another rectangular monopole. The advantage of the slot is that it supports a wide range of modes that by its role open the radiation band from 1.65 to 3.6GHz. The antenna meets three challenging parameters: compact size, multiband operation including low frequency bands, and low SAR radiation. Good agreement is noticed between the experimental and simulated results. [ABSTRACT FROM AUTHOR]

In this paper, an open slot antenna fed by a U shaped monople is introduced. The slot antenna radiates in the range from 1.6 to 3.44 GHz and from 3.8 to 5.7GHz. The slot is formed by an open ring of quarter wavelength at 900 MHz. Thus, the ring acts as a monopole at 900 MHz in addition to a wideband slot radiator in the high frequency range. In order to serve the LTE700 MHz band, another ringe monopole is added to the antenna. The proposed antenna has a -10 dB bandwidth which extends from 674 to 750 MHz, from 872 to 976 MHz, from 1.6 to 3.44 GHz, and from 3.8 to 5.7GHz. The antenna size is 23 x 31 x 1.5 mm³. A prototype of the antenna was fabricated using FR4 substrate (εr = 4.5) with 1.5 mm thickness and loss tangent of 0.025. This paper proposes a new mobile handset antenna structure with low SAR values with compact size that cover most of the mobile operating bands and other wireless applications. The covered bands are the GSM900, DCS1800, PCS1900, UMTS2100, and most of the LTE bands including the LTE700 band. Furthermore, it covers the ISM, WIMAX and the WLAN bands. The SAR calculations are done using the CST 2012 commercial package and the voxel head modal. The SAR values are calculated at different operating bands, different distances, and different orientations. The effect of the human body on the performance of the antenna is tested by calculating the radiation pattern in the presence of the body. The simulation results are compared to the experimental measurements and a good agreement is observed. [ABSTRACT FROM AUTHOR]

A novel dual-band dual-polarized microstrip slot antenna used in mobile base stations is proposed. The antenna supports the operating bands of GSM900 (0.88-0.96) GHz, DCS1800 (1.71-1.88) GHz, PCS1900 (1.85-1.99) GHz, and UMTS2100 (1.92-2.17) GHz. The antenna is fabricated using low cost FR4 dielectric substrates. The antenna is based on two orthogonal rectangle slots centered by a square slot etched on the ground plane and incorporates two orthogonal microstrip feeding lines placed underneath the FR4 substrate on the opposite side of the ground plane to achieve dual polarization. The simulated isolation between the two ports is better than -45 dB overall the operating bands. The measured isolation for the proposed antenna between the two ports does not exceed -30 dB within the operating bands. The average front-to-back ratio is 17.15dB at GSM900, 29.12dB at DCS1800, 18.47dB at PCS1900 and 16.03 dB at UMTS2100. Average antenna gains about 7.7 dBi and 6.6 dBi have been obtained for the lower and the upper bands, respectively. The design is dedicated to the single antenna array element that could be incorporated in an array in order to construct the base station antenna. [ABSTRACT FROM AUTHOR]