Volume 69, Issue 11-12 -

This paper presents, the investigation of tunable components based on LTCC technology, implementing ferroelectric tunable thick-film dielectric. The tunable loaded line phase shifters are fabricated with metal-insulator-metal (MIM) varactors to demonstrate the capabilities of this method for packaging of the tunable components. The MIM varactors consist of one tunable dielectric paste layer that is printed between two silver layers. The tunable ferroelectric paste is optimized for LTCC sintering temperature around 850°C. The phase shifters are fabricated in two different process. They were achieved a figure of merit of 24°/dB (phase shift 192°) at 3 GHz and 18°/dB (phase shift 98°) at 4.4 GHz by using seven unit cells that each unit cell consisting of two MIM varactors.

This paper introduces a frequency reconfigurable hybrid slot antenna fed by coplanar waveguide (CPW) without complex bias network and DC blocking capacitor chips. In order to add reconfigurablility to the antenna, the PIN diodes are equipped in the slots. The antenna is capable of frequency switching at six different frequency bands between 1.7 GHz to 2.5 GHz, which can be used in multiradio wireless systems, such as DCS-1800, PCS1900, UMTS, Wibro and Bluetooth bands. The simulated and measured return loss, peak gain, together with the radiation patterns are presented and compared. Especially, the radiation patterns are stable at different frequency.

This paper presents a compact MIMO antenna for LTE 700, LTE 2300 and LTE 2500 applications. The antenna is configured by two symmetrical quarter wavelength meandered lines on the front side and a slotted ground plane at the back side. An decoupling patch is used to achieve good isolation between two symmetrical quarter wavelength meandered lines.

In this paper, a printed slot antenna for ultra-wideband dual polarization is proposed and experimentally demonstrated. The slot is L-shape and its two arms are individually microstrip fed for producing the orthogonal polarizations. The slot arms and the microstrip feed lines are step sectioned for wideband impedance matching. For isolation purpose, a slant narrow metallic stub is inserted at the junction of the slot arms. The antenna has an impedance bandwidth of 118% (3.1–12 GHz) and isolation of around 20 dB over most of the band. The radiation patterns are nearly omnidirectional with a peak gain varying from 3 to 6 dBi. For assessing the diversity performance of the antenna, the envelope correlation coefficients are computed from the simulated and measured S-parameters and found to be within acceptable limits. With a compact, single substrate design, the antenna is expected to be useful for printed circuit ultra wideband applications requiring dual polarization features.

In this article, started from analyzing the basic principle of band-notched characteristics, a feasibly method used for band-notched antenna is demonstrated and the equivalent circuit for this method is designed. A novel UWB antenna is designed. Based on this method, two stubs which can be equivalent to shorted stubs in parallel configuration are added to realize dual band-notched characteristics. Simulated and measured results all show that the UWB antenna yields an impendence bandwidth of 2.0–10.6 GHz by defining VSWR ≦ 2, and two obvious band-notched functions (3.27–3.83 GHz, 4.60–5.90 GHz) occur at the working bandwidth of WIMAX (3.3–3.7 GHz) and HiperLAN/2 (5.15–5.35 GHz, 5.47–5.725 GHz), so the electromagnetic interference between UWB application and WIMAX, HiperLAN/2 can be suppressed.

A new type of two-dimensional (2D) composite right/left-handed transmission lines (CRLH TL) which is composed of four one-dimensional (1D) CRLH TL is proposed in this letter. Each 1D CRLH TL consists of three metallic vias added for shunt inductance and an etched patch slot for series capacitance. Based on this structure, an antenna operating on zeroth-order resonance (ZOR) and first-order resonance (FOR) is designed and fabricated. By taking advantage of coaxially center feed and symmetric structure, a well omnidirectional radiation in XoY plane both in ZOR and FOR and a homogeneously suppressed cross-polarization is obtained. Also, the antenna has a gain value of 2.06 dB in ZOR f 1 = 3.52 GHz and 2.94 dB in FOR f 2 = 5.25 GHz, respectively.

In this study, a novel nano antenna is designed in order to convert the high frequency solar energy, thermal energy or earth re-emitted sun’s energy into electricity. The proposed antenna is gold printed on a SiO 2 layer, designed as a circular edge bow-tie with a ground plane at the bottom of the substrate. The Lorentz-Drude model is used to analyze the behavior of gold at the infrared band of frequencies. The proposed antenna is designed by 3D-electromagnetic solver, and analyzed for optimization of metal thickness, gap size, and antenna’s geometrical length. Simulations are conducted in order to investigate the behavior of the antenna illuminated by the circularly polarized plane wave. The numerical simulations are studied for improving the harvesting E-field of the antenna within 5 THz–40 THz frequency range. The proposed antenna offers multiple resonance frequency and better return loss within the frequency bands of 23.2 THz to 27 THz (bandwidth 3.8 THz) and 31 THz to 35.9 THz (bandwidth 4.9 THz). An output electric field of 0.656 V/µm is simulated at 25.3 THz. The best fitted gap size at the feed point is achieved as 50 nm with the substrate thickness of 1.2 µm.

A Ka band GHz Transverse Electromagnetic (GTEM) cell with a large uniform volume is proposed in this paper. We calculated the characteristic impedance of the GTEM cell transition, and designed a wideband, low insertion loss，simple structure of the GTEM cell transition. The characteristic impedance of the main part of the GTEM cell is calculated with a new simple and effective method, and the larger uniform fields are be got by suppressed higher TE modes with narrow slot on the septum. The feasibility of the method was assessed with simulation software CST. It provides a method to solve the contradiction between the upper limit frequency and the volume of the GTEM Cell.

In this paper, Plotkin’s construction is employed to buildup longer length polar codes with the help of shorter length polar codes. Firstly, we present the multi-level code construction steps for non-cooperative communication schemes. Secondly, we extend the proposed multi-level polar code construction to coded-cooperative scenarios due to the parallel split in the proposed encoding scheme. Since, relay plays a pivotal role in the overall bit error rate (BER) performance of the coded-cooperative schemes, therefore, an efficient criteria of information bit selection at the relay is also presented. Furthermore, we propose a novel joint successive cancellation decoding scheme, which is employed at the destination and provides significant coding gains. Various numerical simulations show that the proposed polar coded-cooperative scheme (PCCS) scheme not only outperforms non-cooperative polar coded scheme but also the existing cooperative schemes for polar codes under identical conditions over an additive white Gaussian noise (AWGN) and quasi-static Rayleigh fading channels.

This paper investigates the capacity of the secondary user (SU) in a cognitive radio (CR) network in Rayleigh fading environments. Different from existing works where perfect channel state information (CSI) or channel distribution information (CDI) of the interference link from the SU to the primary user (PU) is assumed to be available, this paper assumes that only partial CDI is available. Specifically, we assume the distribution parameter is unknown and estimated from a set of channel gain samples. With such partial CDI, closed-form expressions for the ergodic and outage capacities of the SU are obtained under the transmit power and the interference outage constraints. It is shown that the capacity with partial CDI is not degraded compared to that with perfect CDI if the interference outage constraint is loose. It is also shown that the capacity can be significantly improved by increasing the number of channel gain samples.

The performance of navigation systems is always reduced by unwanted multipath propagation. This is especially of practical importance for airborne navigation systems like the instrument landing system (ILS) or the VHF omni directional radio range (VOR). Nevertheless, the quantitative analysis of corresponding, potentially harmful multipath propagation disturbances is very difficult due to the large parameter space. Experimentally difficulties arise due to very expensive, real scale measurement campaigns and numerical simulation techniques still have shortcomings which are briefly discussed. In this contribution a new universal approach is introduced on how to measure very flexibly multipath propagation effects for arbitrary navigation systems using a channel sounder architecture in a scaled measurement environment. Two relevant scenarios of multipath propagation and the impact on navigation signals are presented. The first describes disturbances of the ILS due to large taxiing aircraft. The other example shows the influence of rotating wind turbines on the VOR.