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In this paper, two multiband MIMO antennas for mobile handsets are proposed. The first antenna is capable of covering GSM900, GSM1800, GSM1900, and UMTS. It has two loop type antenna elements, which are with the same structures and dimensions. The dimensions of the antenna element is 22.5∗25mm2. Two structures which are slot and inverted-L branches on the ground, are used to minimize the mature coupling...
This paper proposes a novel heart-shaped dual band-notched UWB antenna with compact and simple structure. The antenna comprise of a microstrip feeding line, a heart-shaped patch to achieve UWB characteristic, and a defected ground with bevels to obtain good impedance match and stable gain in the operating band. The band-notched characteristic is achieved by a U-shaped slot on the patch and a pair...
Two kinds of novel miniaturized dual-band antennas are proposed, which is worked as Radio Frequency Identification (RFID). Their arms carried by bending or simply fractal like tree form based on conventional dipole antenna So they can realize electric small size and dual band with its bent arms. This paper gives design of unequal length arm rounded U-shaped antenna and round notched antenna Experiment...
Gradient metasurfaces (GMs) can provide additional parallel wave vectors for reflected waves and thus anomalous reflection can be induced. Hence, EM wave reflection can be redirected using reflective GMs. In this paper, we focus our research on the manipulation of EM wave reflection using reflective GMs under normal incidence both theoretically and experimentally. The design theory of reflective GMs...
For inspecting on the nonlinearity of RF channel, measurements with novel multi-tone excitations are developed based on a vector network analyzer (VNA) and a multi-tone generator. Many differences have been found in both statistical averages and variances of the transmission function. These differences between statistical averages reflect the nonlinearity of RF channel, and the differences between...
This paper presents the study of radio propagation characteristics in disaster scenarios. Body effect on the propagation loss is evaluated via measurement. Moreover, experiments both in a typical indoor environment and in ruins are conducted for comparison. The attenuation and coherence bandwidth are analyzed.
The purpose of this research paper is to investigate the defects detecting technique in printed electronics by the third harmonic measurements. Various types of defects were introduced on the samples and the third harmonic signal was measured using a component linearity tester (Radiometer CLT1). The relationship between the defects in the printed samples and the third harmonic signal and the third...
The spectrum analyzer is widely used for RF signal measurement. In this paper, remarkable features of MS2726C handheld spectrum analyzer are introduced simply. Typical application examples of MS2726C handheld spectrum analyzer, such as satellite transponder spectrum measurement, very low signal level measurement, multiple marker measurement and EMI direct measurement below 10GHz, are presented. Measuring...
This paper reports a polarization selective one-way microwave absorber based on composite metamaterial slabs. The polarization selective one-way absorber allows a linearly polarized electromagnetic wave to be absorbed along one particular incident direction and to penetrate through it along the opposite direction. For the cross-polarized wave, the direction dependent propagation properties are reversed...
In this paper, a new high-QL resonator using a combination of SIR (Stepped Impedance Resonator) shaped hairpin resonator, interdigital capacitor, and meander line with μ-near zero (MNZ) metamaterial is suggested. Interdigital capacitor is applied to a resonator to get high-QL performance and to obtain μ-near zero characteristic for size reduction. Also, the compact elliptic function and slow-wave...
This paper presents the methods to improve load modulation in Doherty along with two modified GaN Doherty power amplifiers (PAs) with high efficiency and linearity at large back-off power for 100 MHz LTE-advanced application. To improve load modulation, the peaking amplifier is designed to achieve similar output current with that of the carrier amplifier by choosing optimal load impedances in class...
In this paper, a novel wideband harmonic phase reference (HPR) based on non-linear transmission line (NLTL) design is proposed. Aside from theoretical analysis, the additional characterization method, including the output spectra and timedomain signal, is performed as well. Due to the HPR is of great importance to NVNA, design of the HPR should be improved to extend the measurement bandwidth of NVNA,...
This paper presents a sub-circuit-based method to model the passive distribution network (PDN) using measured S-parameters. In general modeling method the PDN models have to be transformed into electric networks consists of resistor, inductor and capacitor components. These modeling processes generally take much time and need repeated adjustments. The sub-circuit-based modeling method converts the...
Absorbing material has excellent attenuation ability to EM wave in high frequency. LC filter filled with absorbing material can realize high insert loss, above 80 dB, between 10 kHz and 110 GHz. This text first introduce the principle of absorbing wave of absorbing material, and then discussed eight compounded absorbing material's attenuation ability to high frequency EM energy. At last is the conclusion.
In this paper, RCS reduction based on metamaterial absorber (MA) structure is investigated in microwave frequency band. The measured results for conducting plane and dihedral angle reflectors coated with metamaterial (MM) layer and FR-4 dielectric layer are presented, which is carried out in an open area test site. Significant RCS reduction by the MA structure is achieved. For the planar MA, the maximum...
A surface current automatic measurement technology has been introduced, and based on the automatic measurement software we realized the automatic measurement of the direction and the magnitude for the surface current. A VC== program is used to show the surface current distribution that is more convenient to research the characteristic of the surface current. And this is also used in the area of ground...
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