Multiband Design Research Articles

Design of compact multiband MIMO antenna for the mobile handsets

ABSTRACTA compact multiband MIMO antenna with four cubic elements covering DCS1800, PCS1900, UMTS2100, LTE2300, WLAN 2.4 GHz and WiMAX 3.5 GHz bands for the mobile handhelds is presented. For each cubic element, a novel structure with slots around the feeding point is designed for the impedance matching and a parasitic element under the radiating cubic element is designed for the bandwidth enhancement. To improve the performance of the signal correlation in the MIMO system, four interdigital structures are etched in the ground plane to achieve great isolation within a wide frequency band. The obtained isolation between each two ports is less than −20 dB in the wide operational bandwidth and the envelope correlation coefficient is reduced below 0.08. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2411–2415, 2016

Design of triple bandpass frequency selective surface in terahertz wave band for radio astronomy

A single screen terahertz frequency selective surface (FS) using the improved split ring resonators (SRRs) is designed in this paper. The resonance unit of an improved SRR consists of an open seam metal patch, while the physical size of the open seam metal patch will directly affect the stepped impedance characteristics. In the paper, LC equivalent circuit model for the improved SRR unit structure is established to extract the equivalent circuit model parameters. Then the relationship between the fundamental frequency of the FSS formula and the harmonics is obtained from the basic theory of the transmission line. Compared to the traditional uniform SRR, the control of multi-band in the improved SRR is more flexible. It is an outstanding characteristic for multi-band FSS design. Based on this characteristic, the triple-band terahertz FSS centered at 0.46, 0.86 and 1.03 THz respectively is designed successively, which can be used in radio astronomy application. By using HFSS 13.0 electromagnetic software simulation, many important indicators such as the key parameters that affect the transmission characteristics of the FSS, periodic intervals, miniaturization degree and the sensitivity of the incidence angle have been studied and analyzed. Both the theoretical analysis and simulated results demonstrate the validity of the method. The triple-band FSS using the improved SRR has a lot of reformative performances. It is shown that the reflection coefficients of triple-band FSS using the improved SRR are -37.6 dB, -13 dB, and -19.6 dB, respectively. On the other hand, it owns the stable frequency response characteristics in the 0°–60° range, which is beneficial to a large incidence angle. In addition, a high degree of miniaturization and the low loss characteristics are the another two significant advantages of this FSS. This triple-band FSS with improved SRR has potential applications in the terahertz frequency radio astronomy polarizer, beam splitter, mirror and resonator mirror, etc.

Digital Filter Application for Squelch on Industrial Frequency Noise and its Harmonic Waves Interference

Industrial frequency and its harmonious waves are one of the main interferences in electronic measurement, which will cause severe influence on test accuracy. Digital filter is better than analog filter at resolution; furthermore multi-band stop digital filter design is unrealizable for analog filter design method. This paper designs an FIR(Finite Impulse Response) multi-band stop digital filter to reject the noise of 50 Hz and its harmonic waves from power network, whose stop bands are respectively as 48~52 Hz, 98~102 Hz and 148~152 Hz. Simulation results prove that the noise can be depressed to 30 dB. To analyze the filtered signal can improve accuracy of the test system. The whole course includes two parts, which are filter mathematical modeling and filter algorithm implementation on worksite data.

Controllable miniature tri‐band bandpass filter using defected microstrip structure

A multi-band microwave filter design method by using the defected microstrip structure (DMS) is developed. A new DMS bandpass filter with a tri-band is designed, fabricated and measured, and the experiment demonstrates the new proposal. The new DMS filter has the advantages of a compact and simple circuit topology, miniature circuit size, individually controllable centre frequencies and individually tunable bandwidths.

Compressive sensing‐based approach to the design of linear robust sparse antenna arrays with physical size constraint

In sparse arrays, the randomness of antenna locations avoids the introduction of grating lobes, while allowing adjacent antenna spacings to be greater than half a wavelength. This means a larger array size can be implemented using a relatively small number of antennas. However, careful consideration has to be given to antenna locations to ensure that an acceptable performance level is achieved. Model perturbations can also cause steering vector errors, which in turn cause discrepancies in the array's response, making robust arrays desirable. This study presents various compressive sensing-based methods that can solve this problem, while also imposing the antenna size as a constraint on the minimum adjacent antenna separations. Narrowband and multiband design examples are presented to verify the effectiveness of the proposed design methods, with comparisons being drawn with a previously proposed genetic algorithm-based approach.

Genetic‐based design of a tetra‐band high‐efficiency radio‐frequency energy harvesting system

In this study, we exploit genetic algorithms to design a rectenna required to harvest ambient radio-frequency (RF) energy from four different RF bands in critical (ultra-low power) conditions. For this purpose a set of multi-resonant annular-ring patch antennas are pixel-wise described inside an electromagnetic simulator to provide the `population' of individuals among which the genetic tool is able to select the most adapted one with respect to the design specifications. The further use of circuit-level non-linear simulation tool, based on Harmonic balance technique, allows the rigorous multi-band design of the whole rectenna system in RF stationary conditions at several received power levels. The result is a novel compact, lightweight and highly efficient tetra-band rectenna, able to harvest RF energy from GSM 900, GSM 1800, UMTS and WiFi sources available in the ambient. At these frequency bands high radiation efficiency is desired as an essential prerequisite for optimally handling very low-power densities. Very good agreement with measurements of both the radiating and rectifying designs is demonstrated in real office scenarios. Finally the rectenna is connected to a power management unit and the resulting assembly is tested in terms of stored energy while harvesting from a mobile cell-phone call.

Wideband and Multiband Antenna Design and Fabrication for Modern Wireless Communications Systems

One of the major challenges due to spectrum scarcity in modern wireless communication is on antenna design that can serve a non-contagious frequency spectrum. In this paper, wideband and multiband design approaches are proposed to produce antennas that can serve various wireless technologies using different frequencies from 2.3 to 6.0 GHz, covering WiFi frequencies at 2.4-2.48 GHz, 5,15-5,35 GHz and 5,725-5,825 GHz, as well as WiMax frequencies at 2.3-2.4 GHz, 2.495-2.695 GHz, 3.3-3.8 GHz, and 5.25-5.85 GHz. The wideband and multiband antenna were implemented on an 0.8 mm thick of FR4 epoxy dielectric substrate with permittivity er=4.3. The return loss of 10 dB can be achieved for 2.3 to 6 GHz in wideband antenna, and a tripe band of 2.3-2.8 GHz, 3.3-3.7 GHz, and above 4.6 GHz in multiband antenna. The gain of both antennas increases almost linearly from 0 dB at 2.3 GHz to around 4.5 dB at 6 GHz, except for the stop band at 2.8-3.3 GHz which has a significant drop of gain, corresponding to the stop frequency band. Antenna radiation pattern is bidirectional at x-y plane and nearly omnidirectional at y-z plane, and shows a similar patern for both wideband and multiband design approaches.

Multi-band design for one-dimensional phononic crystals

Periodic composites with band gaps that prevent the propagation of elastic waves in certain frequency ranges can be used to control waves for a variety of engineering applications. Although studies on the characteristics of these materials, which are called phononic crystals (PCs), have yielded a large number of positive results in recent years, there is still a lack of effective design methods. In this work, a multi-objective optimization approach based on the band gap mechanism and an intelligent algorithm is used to design a one-dimensional (1D) slab construction of PCs. The design aims to fit pre-determined bands by arranging the available materials properly. Obtained by analyzing the wave transmission in periodic layers, the objective functions are linked to the optimization program to obtain a proper solution set. The results of the numerical simulations demonstrate that without constructing complicated structures, the design method is able to produce PCs that overcome the limitations of two-component PCs and hence can feasibly and effectively achieve the design targets. The design approach presented in this paper can be extended to two- or three-dimensional systems and has great potential for the development of sound/ultrasound isolation structures, multiple band frequency filters, and other applications.

Scheme Selection of Camouflage Screen Design Based on Hierarchical Grey Relational Analysis

As many influence factors and technical problems should be taken into account in the scheme selection decision of multi-band camouflage screen design, a method based on hierarchical grey relational analysis combing analytic hierarchy process (AHP) and grey relational analysis (GRA) was developed. The hierarchy model was constructed firstly, and the judging matrixes were established through analytic hierarchy process. The weight value for each index which effects the evaluation was determined accordingly. The relational degree between an individual alternative scheme and the ideal alternative and the worst alternative are calculated by grey correlation degree, and the evaluation degree is calculated according the grey correlation degree and weight value. Based on the relational degree a quality order for the alternative schemes can be obtained. Experiment was carried out, which proved that the method mentioned in this paper had both strict mathematical theory basis and good practical utility. This method can be also used in scheme selection decision of other camouflage designs.

Multi-Band Radar Receiver Design Approach for Minimum Bandpass Sampling

Multi-frequency radars, which are employed in a plurality of emerging applications, exploit the echoes for different bands that come from illuminated targets. A compact multi-function architecture that makes use of direct sampling could be a preferable choice for these new-generation radar systems, with RF front-end design a first step in their development. Here, within the framework of multi-frequency radars, an analytical tool for simultaneously acquiring the signal bands by using the minimum sub-Nyquist sampling frequency is addressed. Although the dual-band radar scenario is exhaustively analyzed, keys to understand the acquisition of more-than-two-band systems are also provided. Moreover, as the core of the associated RF architecture to carry out arbitrary multi-band signal pre-selections, a new class of microwave planar multi-passband filters based on stepped-impedance-line signal-interference concepts is reported. Also, for validation, the construction and testing of a microstrip spectrally-asymmetrical dual-passband filter prototype for a specific example of minimum-sampling dual-frequency radar RF front-end are shown.

Planar Compact Slot Antenna With Multi-Band Operation for IEEE 802.16m Application

A novel multi-band design of planar slot antenna with compact operation for IEEE 802.16m WiMAX system is proposed. With the use of C- and inverted L-shaped slots, multi resonant modes close to 2.6/3.5/5.5 GHz bands can be excited to meet the specifications of WiMAX system (IEEE 802.16m). The obtained impedance bandwidth across these operating bands can reach about 525/743/813 MHz for the 2.6/3.5/5.5 GHz bands, respectively. We derive more than 10% reduction in antenna size and gain compact operation only from 32 14 0.8 antenna dimension. The measured peak gains and total radiation efficiencies are about 3.0/4.3/5.2 dBi and 88/95/97% for the 2.6/3.5/5.5 GHz bands, respectively, with nearly omni-directional pattern in the -plane.

Dual-band metamaterial with a windmill-like structure

A broadband negative refractive index metamaterial based on a windmill-like structure is proposed, and investigated numerically and experimentally at the microwave frequency range. From the numerical and experimental results, effect media parameters are retrieved, which clearly show that two broad frequency bands exist in which the permittivity and permeability are negative. The two negative bands are from 9.1 GHz to 10.5 GHz and from 12.05 GHz to 14.65 GHz respectively, and the negative bandwidth is 4 GHz. Due to the good bandwidth performance, the metallic cell with double negative property obtained in this paper is suitable for use in the design of multiband or broadband microwave devices.

Design of Multi-Band, Compact Parasitic Array With Twisted, Helical Directors

A new design for compact parasitic array is suggested in order to achieve multiple bands. The driver is folded for close spacing between the driver and the directors, and the directors are twisted in helical shapes with different radii and heights. The three proposed compact parasitic arrays have two, three, and four helical directors, and the number of directors results in the same number of resonances. At all generated resonances, the maximum measured realized gains in the direction of the directors are greater than 8.6 dBi, and the front-to-back ratios are greater than 9 dB. Both results are similar to those in a conventional two-element Yagi antenna, whilst the proposed design offers multiband operation and smaller overall volume.

Location Optimization of Robust Sparse Antenna Arrays With Physical Size Constraint

The location optimization problem for robust sparse antenna array design is addressed with the aim of finding a set of antenna locations that is robust to norm-bounded steering vector errors. A constraint of the antenna's physical size is also imposed to ensure the antennas can fit into the optimized locations. Narrowband and multiband design examples are provided to verify the effectiveness of the proposed design method.

Pentaband printed antenna for laptop computer

AbstractThis article presents design and measurement of a planar multiband (GSM850/900, DCS, PCS, and UMTS bands) antenna used in a laptop computer. The antenna can be identified by crossly connecting a meandered inverted‐F configuration and a T‐shaped monopole. The inverted‐F part is mainly responsible for GSM‐band operation. To cover the DCS, PCS, and UMTS bands, a T‐shaped monopole is added. Although directly connecting them together, VSWR cannot meet the specification at the higher band. Therefore, an open‐tub is added at bottom end of the T‐shaped monopole. It is investigated that the stub serves as a capacitive match element. After tuning length of this stub, all properties of the pentaband antenna include the bandwidth, radiating pattern, and gain variation can satisfy practical applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:857–861, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25859

PLANAR COMPACT MULTI-BAND C-SHAPE MONOPOLE ANTENNA WITH INVERTED L-SHAPE PARASITIC STRIP FOR WIMAX APPLICATIONS

A novel compact multi-band design of planar C-shape monopole antenna with inverted L-shape parasitic strip is proposed for IEEE 802.16m WiMAX system. The obtained impedance bandwidth across the 2.6/3.5/5.5GHz operating bands can reach about 240/570/4470MHz, respectively. Only with the antenna size of 15£30£0:8mm 3 , the proposed monopole antenna has the compact operation with more than 25% antenna size reduction. The measured peak gains and radiation e-ciencies are about 1.6/1.9/2.9dBi and 91/96/94% for the 2.6/3.5/5.5GHz operating band, respectively, with nearly omni-directional pattern in the XY -plane.

A 0.18 μm CMOS dual-band low power low noise amplifier for a global navigation satellite system

This paper presents a dual-band low noise amplifier for the receiver of a global navigation satellite system. The differences between single band and multi-band design methods are discussed. The relevant parameter analysis and the details of circuit design are presented. The test chip was implemented in a TSMC 0.18 μm 1P4M RF CMOS process. The LNA achieves a gain of 16.8 dB/18.9 dB on 1.27 GHz/1.575 GHz. The measured noise figure is around 1.5–1.7 dB on both bands. The LNA consumes less than 4.3 mA of current from a 1.8 V power supply. The measurement results show consistency with the design. And the LNA can fully satisfy the demands of the GNSS receiver.

Planar multi-band monopole antenna with L-shaped parasitic strip for WiMAX application

A multi-band design of a planar inverted L-shaped monopole antenna with an L-shaped parasitic strip for the WiMAX system is proposed. With the use of L-shaped monopole and parasitic strips, multi-resonant modes close to the 2.6/3.5/5.5 GHz bands are excited to meet the specifications of the WiMAX system (IEEE 802.16e). Also, obtained impedance bandwidth across the operating bands can reach about 270/1000/1250 MHz for the 2.6/3.5/5.5 GHz bands, respectively. With a nearly omnidirectional pattern in the xy-plane, measured peak gains and radiation efficiencies are about 3.7/3.1/4.8 dBi and 68/80/84% at the 2.6/3.5/5.5 GHz operating bands, respectively.

A Novel Modified Multiband Planar Inverted-F Antenna

A novel multiband modified planar inverted-F antenna (PIFA) with a compact single feed is proposed, which covers GSM900 (880-960 MHz), DCS (1710-1880 MHz), PCS (1850-1990 MHz), UMTS (1920-2170 MHz), Bluetooth/WLAN (2400-2480 MHz), WiMAX (2500-2690 MHz), HiperLAN/2 (5470-5725 MHz), and an additional band (4600-4800 MHz). In conventional PIFA, most of time the shorted pin acts as a capacitor load only for impedance matching purpose, which may yield a large ground plane, narrow bandwidth, and large antenna volume due to a long shorted pin to provide enough capacitance. In our design, the shorted pin just acts a short-circuited load, which is an effective way to control the current resonant paths and is a novel way in design a multiband PIFA. Furthermore, with this design and parasitic folded structures, the proposed multiband antenna can be modeled by parallel short-circuited transmission line impedance transformers (TLIT), which can easily create six mentioned frequency bands (from PCS band to HiperLAN/2 band) by adjusting the lengths of folded branches. Measurement result conforms that our multiband design not only provides size reduction of both the antenna and the ground plane but also enhances the bandwidth of the six bands.

A Multiband Inductor-Reuse CMOS Low-Noise Amplifier

This paper presents the design and implementation of a new multiband, multistandard CMOS low-noise amplifier (LNA) that reuses inductors for different frequency bands to minimize chip area. The idea is to adaptively reconfigure a CMOS transistor in either common source or common gate configuration to achieve narrow-band (NB) or wide-band (WB) input matching, respectively, while conveniently reusing input and load inductors for both bands. This architecture is suitable for 802.11 a/b/g and Public Safety Broadband (PSB) applications, where the NB configuration covers wireless local area network (WLAN) 802.11 b/g, while the WB configuration accommodates the PSB at 4.9 GHz and WLAN 802.11 a. Two versions of the proposed idea, a tapped-capacitor and a tapped-inductor input-matched LNA, have each been designed and fabricated in 0.13-mum CMOS and measurement results are demonstrated.