GHz Downlink Research Articles

A droplet-shape inspired wideband bow-tie dielectric resonator antenna for sub-6 GHz and IoT applications

In this article, an approach to realizing a dielectric resonator based bow-tie shaped antenna for the sub-6 GHz, 5G and IoT applications is discussed that utilizes droplet-shaped radiators for its two arms. The droplet-shaped radiating element is systematically derived to obtain a wider bandwidth response by truncating the sides of an aperture-coupled cylindrical DRA operating at HE11δ mode. The proposed bow-tie dielectric resonator antenna (DRA) is a modified dipole structure that uses a balanced line to differentially feed the two radiating segments to attain an overall wideband characteristics. A wideband matching balun circuit facilitates the antenna feeding which produces equal amplitude signals with 180° phase difference at its two output ports throughout the band of interest. The measurement of the proposed antenna confirms that it can serve several 5G bands like n77 (3300–4200 MHz), n78 (3300–3800 MHz), n48 (3550–3700 MHz) and n79 (4400–5000 MHz) with an overall wide bandwidth of 42.7% in the sub-6 GHz range. This planar configuration has a realized gain value ≥7.5 dBi within 3.37–3.91 GHz and it remains higher than 6 dBi almost throughout the working bandwidth of 3.18–4.91 GHz with considerably wide beamwidth. This broadband DRA has a consistent broadsided radiation pattern with cross-polarization discrimination (XPD)> 20 dB and its radiation efficiency varies between 60%–70% within 3.2–4.8 GHz. The antenna occupies a volume 1.2λ×1.2λ×0.1λ corresponding to its lower frequency of operation and it can support many more significant applications including WiMAX (3.3–3.8 GHz), Citizens Broadband Radio Service (CBRS) (3.55–3.7 GHz) and LTE (3.41–3.5 GHz uplink/3.51–3.6 GHz downlink). All these characteristics make this antenna a suitable candidate for use in transceiver modules for indoor communication, base stations, and vehicular communication.

Triple band single layer microwave absorber based on closed loop resonator structures with high stability under oblique incidence

A novel triple-band microwave absorber design which is independent of polarization with extremely high stability under oblique incidence is described in this paper. The proposed absorber structure's unit cell architecture contains three closed loop microstrip resonator components with rotational symmetry. The suggested design engenders three reflection nulls at 2.4 GHz (WiMAX), 5.5 GHz (WLAN) and 7.51 GHz (downlink satellite communication frequencies in the X-band). These gives rise to triple absorption peaks with near-unity (almost 100 %) absorptivity at the mentioned frequencies. The absorber design is fully immune to polarization for both TE and TM modes of propagation. Furthermore, the structure offers very high stability under oblique incidence for both TE and TM modes where beyond 90 % absorptivity is obtained up to 520 incident angles and beyond 80 % absorptivity is achieved up to 750 incident angles. The unit cell size is 0.12λ0 × 0.12λ0, where λ0 is the wavelength corresponding to the lowest absorption frequency. The advantage of the proposed structure over other reported absorbers is assessed by its superiority in terms of multiband functionality, full polarization insensitivity, stability under oblique incidence and compactness. A prototype of the proposed absorber was fabricated and the measured results agree closely with the simulation results.

Optimum Design of a Novel Electronically Reconfigurable Reflectarray Antenna for X/Ku Band Applications

The frequency reconfigurable reflectarray (RRA) reported in this paper provides a pencil beam at three frequencies captivating the need for satellite broadcast television at uplink and downlink frequencies in Ku band and X band. To achieve such frequency reconfiguration, a unit cell developed and simulated based on an infinite array approach is used in integration with four PIN diodes to produce a reflection phase variation of 525°, 415°, and 308° at 14.34 GHz for uplink operation, 12.2 GHz for downlink and 11.9 GHz for X-band performance respectively. In this proposed unit cell, the phase variation for uplink is achieved by varying the size of concentric loops, while in the case of downlink and X-band, reconfiguration controlled by pin diodes is achieved by varying the length of the delay line. With the periodicity of 0.49λ0 (10.5 mm), a 15 15 array with 225 elements is constructed using the designed unit cell on square planar geometry. The paper reports a maximum gain of 25.77 dBi, 25.13 dBi, and 22.7 dBi and 40.22%, 26.46%, and 25.36% of aperture efficiency at 14.34 GHz, 12.2 GHz, and 11.9 GHz respectively. A -3dB gain bandwidth of 8.37%, 4.92%, and 12.18% is achieved at the three operating frequencies by simulation. Hence this reconfigurable reflectarray serves as an emulous alternative to parabolic reflectors and phased array antennas in deep space communication and direct broadcast satellite applications satisfying the high gain pencil beam requirements.

5G NR Network Planning Analysis using 700 Mhz and 2.3 Ghz Frequency in The Jababeka Industrial Area

This research designed a 5G NR network using 700 MHz and 2.3 GHz frequencies with 30 MHz bandwidth in the Jababeka industrial area covering an area of 5600 hectares. The Propagation Model used by Urban Macrocell (UMa) in non line of sight (NLOS) conditions according to 3GPP TR 38901 standard with Synchronization signal-reference signal received power (SS-RSRP) and Synchronization Signal to Interference and Noise Ratio (SS-SINR) parameters. Coverage prediction simulation using Atoll 3.4 consists of 4 scenarios. Scenario 1 uses a frequency of 2.3 GHz downlink, scenario 2 uses a frequency of 2.3 GHz uplink, scenario 3 uses a frequency of 700 MHz downlink and scenario 4 uses a frequency of 700 MHz uplink. Parameters analyzed were signal strength (SS-RSRP > -110 dBm) and signal quality (SS-SINR > 5 dB). The simulation results of scenario 1 get a signal strength of 61% and signal quality of 73.71% from the Jababeka area. Scenario 2 gets 100% for signal strength and 75.35% for signal quality. Scenario 3 gets a signal strength of 72.27% and signal quality of 85.30%. Scenario 4 shows a signal strength of 100% and signal quality of 71.04% from the Jababeka area. Planning with a frequency of 700 MHz shows that the signal strength and signal strength parameters are better than the 2.3 GHz frequency, making it suitable for 5G networks in the Jababeka area. The findings of this study are intended to help Indonesian cellular operators plan and deploy their 5G network.

Active frequency selective surface with switchable response for satellite communications in X and Ka bands

This article proposes an active frequency selective surface (FSS) with application to satellite multi-band antennas in X and Ka bands. The FSS offers two reflective bands at 20 and 30 GHz (downlink and uplink frequencies of broadband communication satellites in Ka-band) under one biasing state, whereas the frequency characteristics are switched in X-band (between 9 and 12 GHz, frequencies used for broadcast satellite services and space exploration) under the second biasing state. The unit cell of the FSS consists of three metallization layers, including four PIN diodes on the bottom layer that provide reconfigurability in X-band. The FSS performance has been analyzed using an equivalent circuit model diagram, which provides a better understanding of the operation principle. The proposed FSS exhibits a robust transmission response for incidence angles up to 40°. Several samples of the FSS formed by a 2 × 4 cell array have been fabricated and measured in a waveguide simulator to confirm the results of the electromagnetic simulations at the lower operating frequencies.

Integrated Tunable Sideband Suppressor for Optical Carrier Reuse in Millimeter-Wave Radio-Over-Fiber Transmission

An integrated Si photonic tunable sideband suppressor is presented for application of remote optical carrier reuse. This tunable sideband suppressor is constructed by a two-rings-coupled Mach Zehnder interferometer with a tuning function to synthesize a box-like, narrow band-pass filter through dual Fano resonance interference. By varying the resonant wavelengths of the ring resonators, we can tune the suppression band adapted to the working millimeter wave (mmWave) frequency. We demonstrate a suppression ratio more than 25 dB on both 28 and 39 GHz downlink mmWave radio-over-fiber (RoF) signals. By applying this component in a bi-directional mmWave RoF system, we observe the quality of the uplink signal modulated on the recycled optical carrier is almost the same as that modulated on a clean laser source without extra power penalty. Since the sideband suppressor is made by Si photonic circuits, it potentially can be integrated with other high-speed Si photonic components to implement an on-chip mmWave radio-over-fiber transceiver.

A novel bidirectional RoF link with compensated SBS and RB for 16-QAM OFDM based mm-wave downlink and uplink vector signal generation and transmission on a single fiber

A novel bidirectional RoF link with compensated SBS and RB for 60 GHz OFDM-based 16-QAM downlink and uplink vector signal generation and co-propagation over a single fiber is proposed. At the central station (CS), 60 GHz optical mm-wave is generated and modulated in the optical single-sideband modulation (OSSB) technique by the 16-QAM OFDM downlink vector signal. At the base station (BS), the 60 GHz downlink signal is detected by a high-speed photodetector (PD). The 60 GHz electrical mm-wave signal is transmitted to the user end by an antenna. The uplink carrier is extracted from the unmodulated sideband of the mm-wave downlink vector signal. This reduces the complexity of BS and makes it free from the laser source. The 16-QAM OFDM-based mm-wave uplink signal is received from the user end through an antenna and down-converted to a 10 GHz uplink vector signal. The uplink signal modulates the extracted blank carrier in the OSSB technique. The uplink and downlink vector signals are co-propagated through the standard single bidirectional fiber. Although the carrier reuse over a single fiber reduces the fiber capacity by half, it generates non-linear backscattering such as Rayleigh Backscattering (RB) and Stimulated Brillouin Scattering (SBS). A theoretical analysis is made on the backscattered power and its effect on the fiber transmission. The compensation of SBS by maintaining the SBS threshold and mitigation of RB is carried out by appropriate modulation technique. In addition, downlink and uplink signal with different data rate is transmitted through the compensated bidirectional RoF link, and the transmission performance is analyzed. Based on the analysis, the theoretical model for simultaneous downlink and uplink signal transmission over a single fiber is proposed and verified by the software simulation. The compensated bidirectional RoF link shows up a better performance up to 75 km with negligible power penalty.

Compact Ultrawide Band Metamaterial-Inspired Split Ring Resonator Structure Loaded Band Notched Antenna

A novel compact size ultrawide band planar antenna with band notched characteristics is present. The band rejection characteristic is achieved by loading a pair of metamaterial inspired rectangular split ring resonator (SRR) near the feed line and by etching the SRR slots on a radiating patch. The simulated and measured results reveal that the proposed antenna exhibits the impedance bandwidth over the ultrawide band (UWB) frequency range from 3.1 to 14 GHz with the voltage standing wave ratio less than 2 except for band stop bands at 3.29 to 3.7 GHz (WiMAX band), 3.7 to 4.10 GHz (C-band), 5.1 to 5.9 GHz (WLAN band), and 7.06 to 7.76 GHz (downlink X-band satellite communication), respectively. The proposed antenna fabricated on low-cost FR-4 substrate has compact size of 24 × 20 × 1.6 mm3. The simulation results are compared with measured results and demonstrate good agreement with stable gain over pass bands. The proposed antenna also exhibits dipole-like radiation pattern in E-plane and omni-directional pattern in H-plane. These results led to conclusion that the presented antenna is a suitable candidate for ultrawide band UWB applications with desired band notch characteristics.

Bidirectional OFDM-MMWOF transport system based on mixed QAM modulation format using dual mode colorless laser diode and RSOA for next generation 5-G based network

A hybrid bidirectional orthogonal frequency division multiplexing–millimeter wave over fiber (OFDM-MMWOF) transport system based on mixed quadrature amplitude modulation (QAM) format using dual-mode colorless laser diode and reflective semiconductor optical amplifier for next-generation 5G based networks is proposed and experimentally demonstrated. Here, an orthogonal quadruple frequency MMW is generated via optical heterodyne scheme. In case of downlink transmission, 10 Gbps baseband signal is transmitted over 80-km single-mode fiber (SMF) plus 500-m free space optical (FSO) distance and for the uplink, 5 Gbps baseband signal is transmitted over 80-km SMF plus 100-m FSO distance. For wireless transmission, 12.5 Gbps/60 GHz downlink MMW signal is generated and transmitted over 80-km SMF as well as 100-m wireless distance. 6.5 Gbps/30 GHz uplink MMW signal is communicated over 80-km SMF plus 50-m wireless distance. OFDM scheme with mixed QAM modulation technique enhances our spectral efficiency and simultaneously reduces inter symbol interference, inter-carrier interference, dispersion, etc. for long reach communication. The feasibility and reliability of our system is established by achieving low bit error rate (10-3), good error vector magnitude (<10.5% for 32 QAM and < 12.5% for 16 QAM), appropriate signal to noise ratio, and clear constellation diagram.

A compact flower slotted dual band notched ultrawideband antenna integrated with Ku band for ultrawideband, medical, direct broadcast service, and fixed satellite service applications

AbstractA compact flower slotted antenna (FSA) for dual band eliminated ultrawideband (UWB) integrated with Ku band applications is proposed. The basic FSA with modified ground structure is utilized for obtaining fractional bandwidth of 137% (3.45‐18.45 GHz). The dual band eliminated frequencies are achieved by a via hole to eliminate 5.39 to 5.90 GHz (upper WLAN band) frequencies and by utilizing symmetrical inverted L‐shaped parasitic elements to notch 7.30 to 7.75 GHz (downlink of X‐ band satellite communication link) frequencies. The FSA is having a compact size of 16 × 22 mm2 printed on low cost FR‐ 4 substrate with two band notched characteristics, nearly omnidirectional radiation characteristics and stable gain over UWB frequency range makes it suitable for portable UWB systems.

Hexa-band suppression characteristics from a fork-shaped UWB-MIMO antenna loaded with complementary split-ring resonator and slots

In the present article, a fork-shaped UWB-MIMO antenna is designed and experimentally tested to achieve hexa-band rejection characteristics. Initially, the proposed array consists of two fork-shaped radiators and a reduced ground with a vertical stub, designed to cover a large bandwidth from 3.64–12.2 GHz and high port-to-port isolation. Furthermore, each fork-shaped radiator is defected with two U-shaped slots, inverted U-shaped slot, complementary SRR and a pair of Z-shaped slots to eliminate the interfering frequency bands at 3.95 GHz (downlink C-band), 4.8 GHz (INSAT), 5.35 GHz (WLAN), 6.19 GHz (uplink C-band) and 8.4 GHz (ITU-8) respectively. The reduced ground is loaded with two G-shaped slots to suppress the interfering amateur radio band (10.01–11.27 GHz). The total volume occupied by the proposed array is 21.5 × 57 × 1.64 mm3. The diversity performance of the proposed array is characterized by low ECC, high DG, high MEG, low CCL and stable TARC characteristics. A close resemblance is achieved between the simulated and experimental results.

Rectangular DR-based dual-band CP-MIMO antenna with inverted Z-shaped slot

ABSTRACT In this paper, a dual-band circular polarised (CP), Multiple Input Multiple Output (MIMO) antenna with bi-directional polarisation is presented. Designed antenna is operating at two frequency bands i.e. 5.4 GHz–6.2 GHz and 7.0 GHz–7.4 GHz. A rectangular dielectric resonator (DR) is excited by two ports for designing an MIMO antenna system. To generate the Circular polarisation, ground plane is modified by etching an inverted Z-shaped slot. The fundamental mode , and higher order mode , are generated in the antenna structure due to the specified geometry which excites the circular polarisation. 3-dB axial ratio (AR) bandwidth of 300 MHz (5.7 GHz–6.0 GHz) and 200 MHz (7.0 GHz–7.2 GHz) is obtained for the lower and upper bands, respectively. Maximum isolation is 19 dB, and 15 dB for the targeted bands have been achieved. S-parameters, gain and radiation pattern are measured to authenticate the simulated results. Envelope correlation, diversity gain, mean effective gain and channel capacity loss are calculated from the measured parameters; their values lie within the optimum range. Results show that antenna is suitable for WLAN 5.5/5.8 GHz and X-band downlink communication at 7.0 GHz.

A 20/30 GHz Reflectarray Backed by FSS for Shared Aperture Ku/Ka-Band Satellite Communication Antennas

This letter presents a dual-polarized and dual-frequency reflectarray backed by a frequency selective surface (FSS) with application to shared aperture Ku / Ka -band satellite communication antennas. The reflectarray has been designed to operate simultaneously at 20 and 30 GHz (downlink and uplink frequencies in Ka -band) using a single-layer configuration, where the printed elements are etched on the upper substrate of a two-layer triband FSS. The FSS has been designed to be transmissive at 12 GHz (downlink frequency in Ku -band) and reflective at 20 and 30 GHz. An 18 × 18-cm2 prototype has been fabricated and tested, showing a good matching with the simulations. The measured gains are 28.5 dBi at 20 GHz and 32.25 dBi at 30 GHz.

Three-Dimensional Dual-Band Dielectric Resonator Antenna for Wireless Communication

A three-dimensional dual-band dielectric resonator antenna, comprised of five rectangular dielectric resonator (RDR) radiating elements, is proposed for wireless communication applications. The presented multiple-input-multiple-output (MIMO)/diversity antenna system use TE 1δ1 Y and HEM 2δ1 modes of the RDR antenna for the transmission/reception of data. The TE 1δ1 Y mode covers the frequency range from 3.3 to 3.8 GHz, covering Wi-MAX, sub-6 GHz, and LTE (3.41-3.5 GHz uplink/3.51-3.6 GHz downlink) 5G application bands. The HEM 2δ1 mode covers Wi-Fi (5.725-5.875 GHz) and ITS 5.9 GHz (5.875-5.925 GHz) bands. The five RDR antenna elements are excited through coaxial feeds and are arranged in a cubical fashion to cover all directions, except -Z direction. The RDR elements are oriented and positioned to achieve a minimum correlation between the radiating elements. The proposed antenna exhibits a gain of 7 dB in the lower band while 7.2 dB gain is obtained in the upper band.

Design of a Broadband Coplanar Waveguide-Fed Antenna Incorporating Organic Solar Cells with 100% Insolation for Ku Band Satellite Communication.

A broadband coplanar waveguide (CPW)-fed monopole antenna based on conventional CPW-fed integration with an organic solar cell (OSC) of 100% insolation is suggested for Ku band satellite communication. The proposed configuration was designed to allow for 100% insolation of the OSC, thereby improving the performance of the antenna. The device structure was fabricated using a Leiterplatten-Kopierfrasen (LPKF) prototyping Printed circuit board (PCB) machine, while a vector network analyzer was utilized to measure the return loss. The simulated results demonstrated that the proposed antenna was able to cover an interesting operating frequency band from 11.7 to 12.22 GHz, which is in compliance with the International Telecommunication Union (ITU). Consequently, a 3 GHz broadband in the Ku band was achieved, along with an enhancement in the realized gain of about 6.30 dB. The simulation and experimental results showed good agreement, whereby the proposed structure could be specifically useful for fixed-satellite-services (FSS) operating over the frequency range from the 11.7 to 12.22 GHz (downlink) band.

Design and analysis of triple notch ultrawideband antenna using single slotted electromagnetic bandgap inspired structure

ABSTRACTA microstrip line fed pentagonal printed ultra wideband (UWB) monopole antenna with partial ground plane having triple notches is proposed. The realized antenna has an operating bandwidth (VSWR ≤ 2) ranging from 3.1 GHz and continuing beyond 12 GHz. A novel mushroom-shaped slotted electromagnetic bandgap (EBG) inspired structure is used near the feedline to introduce triple notches at CBRS (3.5–3.7) GHz, WLAN (5.15–5.725) GHz and X-band downlink satellite communication (7.25–7.75) GHz frequencies. The band notch characteristics are demonstrated with current distribution and impedance analysis. Further, the proposed structure has stable radiation patterns, gain and group delay in the UWB range except the notch frequencies. Finally, a prototype of the proposed antenna is fabricated and measured results are in good agreement with the simulated results.

Dual Band BPF Based on Parallel Coupled Lines Loaded by Open Stubs for Ku-Band Satellite Applications

This paper presents a dual band Band Pass Filter (BPF) operating at both the downlink and uplink frequency bands for Ku-band satellite applications. The commonly used frequency band in mobile communications satellites is the Ku-band. These mobile satellite systems help connect remote regions, vehicles, ships, people and aircraft to other parts of the world and/or other mobile or stationary communications units, in addition to serving as navigation systems. The structure of the proposed filter is based on parallel coupled microstrip lines and four sections are used. Tuning the two operational bands can be achieved using two open-circuited stubs at the first and last sections of the parallel coupled microstrip lines. The proposed filter is adjusted to operate at 12.54 GHz and 14.14 GHz for downlink and uplink bands, respectively. The proposed dual band BPF is fabricated, measured, and good agreement is obtained between simulated and measured results.

A compact meta-atom loaded asymmetric coplanar strip-fed monopole antenna for multiband operation

In this paper, a compact asymmetric coplanar strip (ACS)-fed monopole antenna is presented. The proposed antenna consists of a tapered shaped radiating element and a meta-atom (complementary split ring resonator-CSRR), loaded in the ground plane which helps in obtaining multiband characteristics with proper impedance matching performance. Antenna with dimensions of 25 × 12.2 × 1.6 mm3 has been designed, fabricated and tested. The experimental result that exhibits of −10 dB impedance bandwidth by the proposed antenna at the center frequency of 2.88 GHz (1100 MHz), 5.78 GHz (1940 MHz) and 7.64 GHz (660 MHz). It covers wireless applications namely wireless local area network (WLAN) 2.4/5.2/5.8 GHz, long-term evolution (LTE) LTE 2.5 GHz, public safety applications 4.9 GHz, worldwide interoperability for microwave access (WiMAX) 5.5 GHz, wireless access for vehicular environments (WAVE) 5.9 GHz and X-band downlink frequency band 7.5 GHz. The antenna has good radiation characteristics in both E-plane and H-plane for all the operating frequencies. The proposed antenna exhibits a better performance compared to the previously reported designs to the existing antenna designs which are discussed in the literature. Moreover, the antenna possesses compact size, the total size occupied by the design is 0.20λ0 × 0.1λ0.

GaN‐HEMT asymmetric three‐way Doherty power amplifier using GPD

A gallium-nitride high electron mobility transistor (GaN-HEMT) three-way asymmetric Doherty power amplifier using an unequal three-way Gysel power divider (GPD) is presented in this study. Considering the output power capacity of transistors, the peaking amplifier was designed to have an output power capacity that is 1.5 times larger than that of the carrier amplifier through the use of a parallel combination of two different power amplifiers. A peaking amplifier that is 1.5 times larger can provide a back-off level of 7.5 dB for another peak efficiency. Two different power amplifiers in the peaking amplifier can work as a single power amplifier through an optimization of the input power division ratio (PDR). To split the input power for the carrier and the two peaking amplifiers, an unequal three-way GPD with an optimized PDR was employed. The implemented Doherty power amplifier for the 2.14 GHz band exhibited a drain efficiency (DE) of 59.5% and an adjacent channel leakage ratio (ACLR) of 27.1 dBc at an average output power of 37.2 dBm (7.2 dB for the output power back-off) for the 2.14 GHz downlink long-term evolution signal, which has a peak-to-average power ratio of 6.5 dB and a signal bandwidth of 10 MHz.

Triple band notched mushroom and uniplanar EBG structures based UWB MIMO/Diversity antenna with enhanced wide band isolation

Triple band-rejection MIMO/Diversity UWB antenna characteristics are described in this paper. Proposed antenna discards worldwide interoperability for microwave access WiMAX band from 3.3 to 3.6 GHz, wireless local area network WLAN band from 5 to 6 GHz and X-Band satellite downlink communication band from 7.1 to 7.9 GHz. Mushroom Electromagnetic Band Gap (EBG) structures helps to attain band notches in WiMAX and WLAN bands. Uniplanar plus shaped EBG structure is used for notch in X-band downlink satellite communication band. Decoupling strips and slotted ground plane are employed to develop the isolation among two closely spaced UWB monopoles. The individual monopoles are 90° angularly separated with stepped structure which helps to reduce mutual coupling and also contributes towards impedance matching by increasing current path length. Mutual coupling magnitude of more than 15 dB is found over whole UWB frequency range. The Envelope Correlation Coefficient is less than 0.02 over whole UWB frequency range.The variations in the notched frequency with the variations in mushroom EBG structure parameters are investigated.The antenna has been designed using FR-4 substrate and overall dimensions is (64 × 45 × 1.6) mm3.