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1

Zastosowanie elektrod grafenowych w przełącznikach na pasmo fal milimetrowych wykonanych w strukturach AlGaN/GaN

Sobolewski Jakub

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2023

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nr 4

155--158

PL

W artykule przedstawiono wyniki badań nad możliwością zastosowania elektrod sterujących wykonanych z grafenu w przełącznikach w.cz. na zakres fal milimetrowych. W badaniach wykorzystano struktury testowe przełączników zintegrowanych z linią koplanarną wykonanych w strukturze półprzewodnikowej AlGaN/GaN w topologii szeregowej i bocznikowej. Na podstawie uzyskanych wyników wykazano możliwości wykorzystania zjawiska zmiany przewodności grafenu pod wpływem napięcia do ograniczenia strat w przełączniku. Wskazano także na możliwość uzyskania poprawy izolacji przy wykorzystaniu elektrod grafenowych. Konieczne jest jednak udoskonalenie procesów technologicznych dla uzyskania wysokiej jakości warstw grafenu.

EN

This paper presents research on application of graphene control electrodes for millimeter wave switches. Series and shunt topology switches integrated with coplanar waveguide in AlGaN/GaN semiconductor structure were examined. Presented results show that it is possible to utilize voltage-controlled conductivity of graphene to reduce losses through gate coupling. They also indicate superior performance of shunt topology and show that application of graphene gate can improve switch isolation. However, to achieve good performance, technological processes have to be improved to increase the quality of graphene layers.

2

Design and analyses of reconfigurable dumbbell-shaped and modified h-shaped DGSs in millimeter wave band

Shairi Noor Azwan, Yasin F. N. M., Othman Adib, Zakaria Zahriladha, Ibrahim Imran Mohd, Majid Huda A., Jamaluddin Mohd Haizal, Ibrahim Ayman Mohammed

Przegląd Elektrotechniczny

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2023

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R. 99, nr 7

96--100

EN

The design and analyses of reconfigurable dumbbell-shaped and modified H-shaped Defected Ground Structures (DGS) in the millimeter wave band (26/28 GHz band) are presented in this paper. The proposed DGSs were designed to be a reconfigurable between bandstop and allpass responses that would be used for 5G interference mitigation and as well as in RF switch design. In the design process, a mathematical model was developed for the analysis of reconfigurable capability between these two responses. Then, based on the E and H field concentration in the electromagnetic (EM) simulation, a suitable location of a PIN diode for the electronically controlled between bandstop and allpass was physically identify on the proposed reconfigurable DGS. Finally, a preliminary verification with an ideal PIN diode (open and short circuited) on the fabricated design was validated with the simulation results. Results showed that the proposed reconfigurable DGS can be changed between bandstop and allpass. The attenuation of the bandstop was more than -20 dB and the insertion loss of the allpass was lower than -3 dB in the 26/28 GHz band.

PL

W artykule przedstawiono projektowanie i analizy rekonfigurowalnych i zmodyfikowanych struktur naziemnych w kształcie hantli (DGS) w paśmie fal milimetrowych (pasmo 26/28 GHz). Proponowane systemy gwarancji depozytów zostały zaprojektowane tak, aby były rekonfigurowalne między pasmowym zatrzymaniem a wszystkimi odpowiedziami przejścia, które byłyby wykorzystywane do łagodzenia zakłóceń 5G, a także do projektowania przełączników RF. W procesie projektowania opracowano model matematyczny do analizy rekonfigurowalnych możliwości między tymi dwiema odpowiedziami. Następnie, w oparciu o stężenie pola E i H w symulacji elektromagnetycznej (EM), odpowiednia lokalizacja diody PIN dla elektronicznie sterowanego między pasmowym ogranicznikiem a wszystkimi przejściami została fizycznie zidentyfikowana na proponowanym rekonfigurowalnym DGS. Na koniec wstępna weryfikacja z idealną diodą PIN (otwartą i zwartą) na wytworzonej konstrukcji została zweryfikowana wynikami symulacji. Wyniki pokazały, że proponowany rekonfigurowalny system DGS można zmieniać między bandstopem a all pass. Tłumienie ogranicznika pasma było większe niż 20 dB, a tłumienie wtrąceniowe wszystkich przebiegów było mniejsze niż -3 dB w paśmie 26/28 GHz.

3

Artificial Magnetic Conductor-based Millimeter Wave Microstrip Patch Antenna for Gain Enhancement

Belabbas Khadidja, Khedrouche Djamel, Hocini Abdesselam

Journal of Telecommunications and Information Technology

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2021

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nr 1

56--63

EN

In this paper, a small (20 × 20 × 2.4 mm) loaded microstrip patch antenna (MPA) with an asymmetric artificial magnetic conductor (AMC) as a ground plane is designed for millimeter wave applications. Two AMC structures are proposed; one has the property of a 0 ◦ reflection phase around 28.4 GHz, with a symmetric geometry, which makes the reflection phase insensitive to variations in both polarization and incident angle. This symmetric AMC structure ensures angular stability which is considered as a major requirement when periodic structures are used as antenna ground planes. The other structure is characterized by an asymmetric geometry and shows an interesting behavior around 28.6 GHz, where a discontinuity in the reflection phase appeared due to the fact that surface impedance nature changed from purely capacitive to purely inductive. This paper studies the effects of the two proposed AMC structures on the performance of MPAs, by using an array of 8 × 8 unit cell elements as an artificial ground plane. Simulation results show that an MPA with a symmetric AMC ground plane offers better impedance matching and a wider bandwidth. Compared with conventional MPAs, gain is enhanced and directivity is improved as well. As far as an MPA with an asymmetric AMC ground plane is concerned, its performance in terms of gain and directivity is higher than that of the conventional solution.

4

Robust Schemes to Enhance Energy Consumption Efficiency for Millimeter Wave-Based Microcellular Network in Congested Urban Environments

Hindia MHD Nour, Qamar Faizan, Ojukwu Henry, Hassan Rosilah, Dimyati Kaharudin

International Journal of Electronics and Telecommunications

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2021

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Vol. 67, No. 3

417--424

EN

Future wireless communication networks will be largely characterized by small cell deployments, typically on the order of 200 meters of radius/cell, at most. Meanwhile, recent studies show that base stations (BS) account for about 80 to 95 % of the total network power. This simply implies that more energy will be consumed in the future wireless network since small cell means massive deployment of BS. This phenomenon makes energy-efficient (EE) control a central issue of critical consideration in the design of future wireless networks. This paper proposes and investigates (the performance of) two different energy-saving approaches namely, adaptive-sleep sectorization (AS), adaptive hybrid partitioning schemes (AH) for small cellular networks using smart antenna technique. We formulated a generic base-model for the above-mentioned schemes and applied the spatial Poisson process to reduce the system complexity and to improve flexibility in the beam angle reconfiguration of the adaptive antenna, also known as a smart antenna (SA). The SA uses the scalable algorithms to track active users in different segments/sectors of the microcell, making the proposed schemes capable of targeting specific users or groups of users in periods of sparse traffic, and capable of performing optimally when the network is highly congested. The capabilities of the proposed smart/adaptive antenna approaches can be easily adapted and integrated into the massive MIMO for future deployment. Rigorous numerical analysis at different orders of sectorization shows that among the proposed schemes, the AH strategy outperforms the AS in terms of energy saving by about 52 %. Generally, the proposed schemes have demonstrated the ability to significantly increase the power consumption efficiency of micro base stations for future generation cellular systems, over the traditional design methodologies.

5

Millimeter Wave Beamforming Training : A Reinforcement Learning Approach

Mohamed Ehab Mahmoud

International Journal of Electronics and Telecommunications

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2021

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Vol. 67, No. 1

95--102

EN

Beamforming training (BT) is considered as an essential process to accomplish the communications in the millimeter wave (mmWave) band, i.e., 30 ~ 300 GHz. This process aims to find out the best transmit/receive antenna beams to compensate the impairments of the mmWave channel and successfully establish the mmWave link. Typically, the mmWave BT process is highly-time consuming affecting the overall throughput and energy consumption of the mmWave link establishment. In this paper, a machine learning (ML) approach, specifically reinforcement learning (RL), is utilized for enabling the mmWave BT process by modeling it as a multi-armed bandit (MAB) problem with the aim of maximizing the long-term throughput of the constructed mmWave link. Based on this formulation, MAB algorithms such as upper confidence bound (UCB), Thompson sampling (TS), epsilon-greedy (e-greedy), are utilized to address the problem and accomplish the mmWave BT process. Numerical simulations confirm the superior performance of the proposed MAB approach over the existing mmWave BT techniques.

6

High Gain Linear 1×4 X-slotted Microstrip Patch Antenna Array for 5G Mobile Technology

Agarwal Samarth, Prachi

Journal of Telecommunications and Information Technology

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2020

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nr 1

50--55

EN

A linear 1×4 antenna array built on the Rogers RT/Duroid 5880 substrate is proposed in this paper to acquire high gain for 5G applications. The proposed design resonates at 38 GHz, i.e. in the Ka-band region, and has small patch dimensions of 5.5×2 mm. The design is simulated using CST studio. The main element consists of X-slot that provides a gain of 6.98 dB with the return loss of –24.25 dB whereas a linear array of 4 elements is made which is fed by the 50Ω m-line using the corporate feeding network which yields a gain of 13.84 dB, as well as the return loss is –15.72 dB. The centreto-centre spacing (d) of elements in the antenna array is 0.8λ.

7

Design of Millimeter-Wave Six-Port Device for LTCC Technology

Słojewska Barbara, Yashchyshyn Yevhen

International Journal of Electronics and Telecommunications

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2020

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Vol. 66, No. 1

37--43

EN

In this paper a design of millimeter-wave six-port device for LTCC (Low Temperature Cofired Ceramic) technology is presented. Furthermore, problems with implementation of the project taking into account requirements of LTCC technology are discussed.

8

Wydajność stacjonarnej radiowej sieci dostępowej systemu 5G pracującej na falach milimetrowych w środowisku podmiejskim

Bechta Kamil, Rybakowski Marcin

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2019

|

nr 6

183--188, CD

PL

Jednym z pierwszych zastosowań standardu telekomunikacji mobilnej piątej generacji (5G) będą stacjonarne radiowe sieci dostępowe pracujące na falach milimetrowych. W artykule tym przedstawiamy analizę symulacyjną wydajności takiej sieci pracującej w paśmie 28 GHz używając modelu propagacyjnego bazującego na pomiarach w środowisku podmiejskim. Analizowany jest wpływ zastosowania układów antenowych stacji bazowych 8x8 i 16x16 uwzględniając efektywny (skuteczny) zysk energetyczny anteny, który jest dużo mniejszy w wielodrogowym środowisku propagacyjnym od nominalnego zysku energetycznego anteny zmierzonego w komorze bezodbiciowej.

EN

One of the first use cases of fifth generation (5G) of mobile communication system will be fixed wireless access operating at millimeter wave frequencies. In this paper we show the simulation results of this kind of network at 28 GHz with the usage of suburban radio propagation channel model based on measurements. We show the analysis of performance of millimeter wave fixed wireless access with 8x8 and 16x16 antenna array at base station taking into account the effective antenna gain, which is much lower in scattering environment than nominal antenna gain measured in anechoic chamber.

9

Investigation of QoS Performance Evaluation over 5G Network for Indoor Environment at millimeter wave Bands

Qamar Faizan, Hindia Mohammad Nour, Abbas Talib, Dimyati Kaharudin Bin, Amiri Iraj Sadegh

International Journal of Electronics and Telecommunications

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2019

|

Vol. 65, No. 1

95--101

EN

One of the key advancement in next-generation 5G wireless networks is the use of high-frequency signals specifically those are in the millimeter wave (mm-wave) bands. Using mmwave frequency will allow more bandwidth resulting higher data rates as compared to the currently available network. However, several challenges are emerging (such as fading, scattering, propagation loss etc.), when we propagate the radio signal at high frequencies. Optimizing propagation parameters of the mm-wave channels system are much essential for implementing in the realworld scenario. To keep this in mind, this paper presents the potential abilities of high frequencies signals by characterizing the indoor small cell propagation channel for 28 GHz, 38 GHz, 60 GHz and 73 GHz frequency band, which is considered as the ultimate frequency choice for many of the researchers. The most potential Close-In (CI) propagation model for mm-wave frequencies is used as a Large-scale path loss model. The results have been collected concerning the capacity of users to evaluate the average user throughput, cell-edge user throughput, average cell throughput, spectral efficiency and fairness index. The statistical results proved that these mm-wave spectrum gives a sufficiently greater overall performance and are available for use in the next generation 5G mobile communication network.

10

An 80 Gbps multi-band access radio over fiber link with single side band optical millimeter-wave dispersion-tolerant transmission without FBG and optical filter

Ashaa R. S., Jayasree V. K., Mhatli S.

Opto-Electronics Review

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2017

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Vol. 25, No. 4

311--317

EN

We are presenting a new low-cost Single Sideband (SSB) modulated Radio-over Fiber (RoF) communication system for millimeter (mm)-wave multiband wireless communication at the frequencies of 40 GHz,80 GHz and 120 GHz. Its principle lies in the Carrier Suppressed modulation through a nested dual electrode Mach–Zehnder Modulator (MZM) and product modulator based baseband signal decomposition. In this novel method, the optical signal is decomposed into different SSB signals using a power splitter and product modulators at the base station. This proposed method uses a different technique for a baseband signal decomposition from the existing method. The proposed signal decomposition technique has reduced the nonlinearities due to the FBGs. The proposed method is compared with the existing method in terms of BER, data rate and OSNR. The simulation results disclose that our proposed scheme outperforms the existing methods at a higher data rate of 80 Gbps with a minimum BER and privileged Q factor.

11

Cloud Cooperated Heterogeneous Cellular Networks for Delayed Offloading using Millimeter Wave Gates

Mohamed E. M.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 1

51--64

EN

Increasing the capacity of wireless cellular network is one of the major challenges for the coming years. A lot of research works have been done to exploit the ultra-wide band of millimeter wave (mmWave) and integrate it into future cellular networks. In this paper, to efficiently utilize the mmWave band while reducing the total deployment cost, we propose to deploy the mmWave access in the form of ultra-high capacity mmWave gates distributed in the coverage area of the macro basestation (Macro BS). Delayed offloading is also proposed to proficiently exploit the gates and relax the demand of deploying a large number of them. Furthermore, a mobility-aware weighted proportional fair (WPF) user scheduling is proposed to maximize the intra-gate offloading efficiency while maintaining the longterm offloading fairness among the users inside the gate. To efficiently link the mmWave gates with the Macro BS in a unified cellular network structure, a cloud cooperated heterogeneous cellular network (CC-HetNet) is proposed. In which, the gates and the Macro BS are linked to the centralized radio access network (C-RAN) via high-speed backhaul links. Using the concept of control/user (C/U) plane splitting, signaling information is sent to the UEs through the wide coverage Macro BS, and most of users’ delayed traffic is offloaded through the ultra-high capacity mmWave gates. An enhanced access network discovery and selection function (eANDSF) based on a network wide proportional fair criterion is proposed to discover and select an optimal mmWave gate to associate a user with delayed traffic. It is interesting to find out that a mmWave gate consisting of only 4 mmWave access points (APs) can offload up to 70 GB of delayed traffic within 25 sec, which reduces the energy consumption of a user equipment (UE) by 99.6 % compared to the case of only using Macro BS without gate offloading. Also, more than a double increase in total gates offloaded bytes is obtained using the proposed eANDSF over using the conventional ANDSF proposed by 3GPP due to the optimality in selecting the associating gate.

12

SiGe HBT wideband amplifier for millimeter wave applications

Krcmar M., Noether N., Boeck G.

Journal of Telecommunications and Information Technology

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2007

|

nr 1

8-12

EN

A wideband amplifier up to 50 GHz has been implemented in a 0.25 žm, 200 GHz ft SiGe BiCMOS technology. Die size was 0.7×0.73 mm2. The two-stage design achieves more than 11 dB gain over the whole 20 to 50 GHz band. Gain maximum was 14.2 dB at 47.5 GHz. Noise figure was lower than 9 dB up to 34 GHz and a current of 30 mA was drawn from a 4 V supply. To the author's best knowledge this is the highest gain bandwidth product of a monolithic SiGe HBT amplifier ever reported.

13

Cost-effective method for generating >20 GHz pulse trains using actively mode locking fiber ring laser

Kim Sun-Jong, Park Chang-Soo

Optica Applicata

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2004

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Vol. 34, nr 1

17-24

EN

This study proposes a simple method to generate high-speed pulse of more than 20 GHz. Its cost performance ratio in an actively rational harmonic mode locking scheme is maximized when the multiplication factor p = 4 and 6. The operation is based on a relatively simple structure using the optical Mach–Zehnder modulator (MZM) biased at the minimum transmission peak and optical filtering via a Mach–Zehnder interferometer (MZI) comb filter. Stable and amplitude-equalized pulse trains with a repetition rate of ~20.345 GHz are successfully demonstrated.