This paper describes a novel FSS which functions as band stop filter to shield the GSM 1800 MHz downlink band. The FSS is designed to operate with the resonant frequency of 1820 MHz which is the centre frequency for the GSM 1800 MHz downlink band. The novelty is attributed to its unique geometry and the circular apertures endowed with it. The proposed geometry provides shielding effectiveness of 20 dB alongside with 133 MHz bandwidth. The structure holds identical response for both TE and TM Modes of polarization. In addition, the geometry with its circular apertures, a hitherto unexplored feasibility serves the purpose of ventilation and heat dissipation. The simulated results are validated using experimental measurements.
An overall Low-Temperature Co-fired Ceramics (LTCC) package solution for X-band T/R module has been presented in this paper. This tile type package contributes to a dramatic reduction in size and weight of the T/R module. Moreover, an obvious merit of ceramic housing is better consistency of Coefficient of Thermal Expansion (CTE), compared with the traditional combination of ceramic board and metal housing. The schematic diagram and 3-D structure of the T/R module have been presented and a novel vertical interconnection based on Ball Grid Array (BGA) has been proposed to connect vias in the lid and those in the stage of the main LTCC pan. The LTCC T/R module has been fabricated and measured. It is compact in size (20×20× 2.6 mm3) and has a weight of 3.5 g. The measured transmit output power is 33±1 dBm in the frequency range from 8.8 GHz to 10.4 GHz, and the measured receive gain and Noise Figure are 29-30.5 dB and 2.6-2.8 dB, respectively.
A wideband dual-polarized antenna with high isolation is presented. Four printed quadrant planar folded dipole placed above a U-shaped reflector are adopted as the main radiation elements. Curved slots cut on the planar folded dipole are used to reduce the size of the antenna. Parameter is studied, and the values are adjusted in order to obtain wideband and compact properties. Measured results show that the antenna achieves a VSWR < 2.0 from 1.64-2.33 GHz. The isolation between the two polarizations is better than 29.5 dB. The radius of the quadrant planar folded dipole is only 34 mm (about 0.18 wavelength at 1.64 GHz).
In this paper, a miniature ultrawideband (UWB) bandpass filter with dual notch bands and wide upper stopband is presented. The ultrawide passband characteristic is achieved using a microstrip to slot line transition, and a wide upper stop band is realized using an elliptical lowpass filter. The dual band notches at 5.46 GHz and 8.04 GHz are obtained by incorporating defected microstrip structure in the input and output section. A prototype of the proposed UWB bandpass filter is fabricated and measured. The equivalent circuit of the proposed filter is also presented. A good agreement between the measured, EM simulated and circuit simulated responses is obtained.
Switch mode power amplifiers offer high efficiency approaching 100% for an ideal case. This paper discusses the operation mode of broadband switch mode class-E power amplifier designed previously by the authors for UHF applications (600-1000 MHz). A method to extract the waveforms at the die reference plane from the time domain analysis using 50 Ω environment systems is discussed. It has been observed that the designed class-E power amplifier operation was not maintained ideally over the entire band; however, it was operating close to the class-E operation.
A single-side-access ring resonator topology is presented. It employs a single quarter-wavelength coupled-line that couples to a one-wavelength ring to exhibit a single-mode resonance with transmission zeros. A global synthesis is presented, in order to control the transmission zeros in its response. As the transmission zeros of the ring resonator maintains their positions when multiple identical rings are used, the global synthesis can further be used for the design of higher order filters with multiple rings. Furthermore, since only one coupled-line is used in the resonator topology, only one section of line is present in the ring, other than the coupled-line. Hence, there will be no second section of the ring that needs to be adjusted to obtain the symmetrical response during its realization, as compared to other types of ring topologies. To show the advantage of the synthesis, it is applied in the design of higher order ring-based bandpass filters, which also involve extra quarter-wavelength coupled-lines to create additional poles. Five bandpass ring filters up to 5th-order were realized using microstrip technology, and measured to validate the proposed concept. Measurement results showing good agreement with those from the simulation are also presented throughout the paper.
In this work, we propose a merged coil structure for wireless chip-to-chip communication technology. Using the proposed coil structure, the chip size can be reduced, and the transmitted power can be improved by approximately 5 dB compared to typical coil structure. To verify the feasibility of the coil, an electromagnetic simulation and a schematic simulation are performed. The coil was implemented using 50-nm digital CMOS technology. From the experimental results, the feasibility was proved.
An ultra-wideband (UWB) antenna with a novel multi-layer frequency selective surface (FSS) reflector is presented. A significant enhancement in the gain has been achieved in a low profile design while maintaining the excellent impedance bandwidth of the UWB antenna. The average peak gain of the antenna has been increased from 4 dBi to 9.3 dBi as a consequence of the use of the FSS reflector. More importantly the gain variation within the frequency range from 3 GHz to 15 GHz is only ±0.5 dB. This is a significant improvement from ±2 dB gain variation of the UWB slot antenna without the reflector. This optimized FSS reflector provides the exibility of mounting a planar antenna close to conducting bodies, including screens and cases.
This paper presents a novel dielectric resonator antenna (DRA) for multiband mobile terminal communication applications. A variation of circular sector dielectric resonator antenna partially coated with metal on its surface is used as the main radiating element. The DRA is fed by a monopole slot-coupled 50-Ω microstrip feed line, which can also provide another radiation mode. By thorough design, the antenna achieves the desired 470-960 MHz band for DVB-H/GSM850/900 operation and 1710-1990 MHz band for DCS/PCS operation. The dimensions of the antenna presented are λ0/17 x λ0/9 x λ0/35 at 470 MHz with appropriate dielectric permittivity εr = 16.
A method to control the transmission zero of TE01δ mode dielectric-resonator (DR) filters for wireless base stations is proposed. Instead of using folder structures, dedicated coupling probes, or extra cavities, as required by conventional techniques, transmission zeros are realized. The feeding probes, extended along ring dielectric resonators, are used to excite the TE01δ mode and introduce transmission zeros. By rotating the angle of feeding position, transmission zeros can be shifted to the lower or the upper stopband. Thus, TE01δ mode dielectric resonator filters with quasi-elliptic responses are realized with only iris coupling components. Based on this method, fourth-order inline TE01δ mode DR filters with different responses are designed and fabricated. Measured results confirm the predicted performance.
An APF (All-Pass Filter) delay module in which eight single-ring resonators are serially cascaded is designed and fabricated. The polymer waveguide used for the realization of the APF delay module is a buried structure whose core width and height are 1.5μm. The core and cladding index are 1.51 and 1.378, respectively, which corresponds to the relative index difference of 8%. In order to use a thermo-optic effect of polymer materials, electrodes are evaporated above the ring resonator to provide heating currents. The time delay is measured to be about 50 ps when 2 rings are in resonance, and about 105 ps and 150 ps, respectively, when 4 and 6 rings of APF are in resonance, respectively. When all of 8 rings are in resonance, the delay is measured to be about 200 ps.
A broadband zeroth-order resonant (ZOR) antenna based on asymmetric coplanar waveguide (ACPW) is presented. By adopting the epsilon negative transmission line (ENG-TL), a zeroth-order resonance mode can be achieved. We propose an asymmetric coplanar waveguide structure which offers the design freedom to realize the broadband ZOR antenna, where the antenna's bandwidth is characterized by an equivalent circuit parameters. The antenna has the compact unit cell dimensions of 5×13.8 mm2. The measured results show that the operating bandwidth is about 1050 MHz (1.90-2.95 GHz), and the peak gain and radiation efficiency are 2.46 dBi and 91% at 2.3 GHz. Owing to the characteristics of broad bandwidth, high efficiency, omnidirectional radiation, and easy manufacturing, the proposed ACPW ZOR antenna is very suitable for modern wireless communication systems (UMTS, WLAN, WIMAX, LTE).
In the above paper , there are two classes of several errors. The first one is related to mistakes/misprints in equations and irrelevant references. The second one is assertions about innovations, which were claimed as ``for the first time" in the literature. In addition to them, the commentators want to attract attentions of the readers with an additional part of comments in order to make more useful and better understanding of the work in . All details about these issues are discussed at following parts:
A low phase noise CMOS complementary cross-coupled LC-tank voltage-controlled oscillator (VCO), implemented with TSMC 0.18 μm 1P6M CMOS technology, is presented. Double pair pseudo-resistance transistors biased by the tapped center of the inductor are utilized to reduce the DC bias current. The circuit consumes 1.55 mA from a 1.5 V supply voltage which saves up to 52.4% power, compared with the conventional one. Furthermore, an adaptive body biasing technique (ABB) is used to overcome the effect of PVT variations. The VCO is tunable from 2.58 to 3.07 GHz and has a phase noise -122.7 dBc/Hz at 1 MHz offset from the 3 GHz carrier. The Figure of Merit (FOM) of the proposed VCO is -188.8 dBc, and the figure of merit including the tuning range (FOMT ) is -193.5 dBc.
In this paper, a novel via-less balanced composite right/left handed transmission line (CRLH-TL) unit cell using defected ground structure (DGS) is presented, and a resonant type antenna based on the proposed CRLH-TL unit cell is designed. Equivalent circuit model is developed to analyze the CRLH-TL unit cell antenna. The resonant frequency is studied, and the resonant frequency tuned by adjusting the dimension of the antenna patch is simulated. The antenna simulated and measured results are presented. The measured central frequency of the proposed antenna is 5.55 GHz. A peak gain of 6.7 dBi with an efficiency of 75.6% is obtained at the central frequency.
This paper presents a novel low-profile antenna with a broadside radiation. The proposed design strategy consists in modifying the layout of a classical Vivaldi antenna, thus resulting in compact dimensions and a broadside radiation pattern. Two different ways of implementing the proposed design approach are presented and discussed. More specifically, experimental data referring to two prototypes on a FR4 substrate with an operating frequency of 2.45 GHz are reported. The first layout has approximately the same dimensions of a Vivaldi antenna and a directivity of about 7 dBi, the second one has more compact dimensions (the dimensions are smaller than the ones of a standard patch antenna) and a directivity of about 5 dBi.
In this paper, a novel miniaturized branch-line coupler (BLC) operating at 1.675 GHz is proposed. Partially meandered lines and dual transmission lines equivalent technology are used as the coupler's shunt arms, producing significant reduction by more than 68% compared with the conventional coupler. Moreover, the coupler can equally divide the input signal with 90° phase of difference while maintaining the initial power from the source with a simple structure. The simulated and measured results are in good agreement. Thereby verifying the design concept.
In this paper, calibration of a microwave power sensor with an adaptor is investigated with direct comparison transfer technique, and mathematically modeled using signal flow-graphs together with non-touching loop rules. The developed calibration model is then implemented practically with a 30 dB attenuator as the adaptor. Its performance is evaluated following the Guide to the Expression of Uncertainty in Measurement and also verified with the Monte Carlo method. Good agreements are observed with all the error |En| ≤ 0.25 over the whole frequency range (up to 18 GHz).
A compact square dc-block bandpass filter with slots is presented. The proposed dc-block bandpass filter using square shapes produces compact size and improved performance as compared to the conventional dc-block bandpass filter using cymbal shapes. Two filters with the same dimensions provide different center frequencies respectively. In other words, the center frequency of the square bandpass filter is lower than that of the cymbal bandpass filter. The center frequency and transmission zeros can also be controlled by the slots of the square shape in the proposed square bandpass filter. The proposed square bandpass filter has an insertion loss of better than 2 dB and a return loss better than 10 dB at center frequency of 7.2 GHz. The proposed square dc-block bandpass filter is optimized by electromagnetic simulator IE3D.
The performance comparison of two configurations of broadband Mach-Zehnder Switches exploiting, respectively, two and three waveguides, assembled into 4x4 matrices is reported in this paper. The simulations are performed by the Finite Element Method and the Finite Difference Beam Propagation Method. In particular, we have found that, to parity of maximum insertion loss, about equal to 1 dB for the single switch and 3 dB for the 4x4 matrix, the proposed three-waveguide configuration exhibits an almost doubled bandwidth Δλ=115 nm, making it suitable for efficient routing of the Wavelength Division Multiplexing signals over photonic Networks on Chip.