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This paper presents a low-profile, horizontally polarized and compact printed antenna radiating parallel to the ground plane. The proposed antenna consists of a small inner feeding loop, a coupled split ring element and a ground plane. The dimension of the proposed antenna is 45 mm × 50.5 mm × 11.6 mm (0.138λ0 × 0.155λ0 × 0.036λ0). From the results, the −10-dB |S11| of the antenna covers the 920-MHz...
A novel band-reconfigurable antenna with stable unidirectional radiation patterns is presented for cognitive radio applications. One wideband mode based on a magneto-electric (ME) dipole and four narrowband modes based on a length-reconfigurable thin dipole are achieved for operation between 0.83 to 2.16 GHz. PIN diodes are used as switches for choosing different operating modes. The ME dipole technology...
In order to apply super high frequency (SHF) bands to small cells, we clarify basic propagation characteristics and shadowing loss due to human body shadowing in the SHF (over 6 GHz) bands based on measurements.
In MIMO transmission scheme, the low correlation between antenna branches is significant to increase the channel capacity. This paper presents simulated results of capacity increase effect in 4×2MIMO channels when the antenna spacing of base station is increased in indoor radio propagation environment where people move around the terminal stationary. In addition, this paper also shows the measured...
We propose a built-in hepta-band monopole antenna that uses a uniquely shape ground plane for wireless mobile terminals. The proposed antenna consists of a triple-band monopole radiating element, as well as a parasitic element with a slit-taper-shaped ground plane to broaden the bandwidth. The antenna was designed and simulated with the FDTD method. Simulation results show that the slit improves antenna...
Improvement of bandwidth of an electrically small and low profile antenna is studied. The bandwidth of electrically small and low-profile antenna in improved using a non-foster element (NFE). This antenna consists of an air gap and two dielectric substrates. The NFE is installed to the meandered line of antenna. As a result, Bandwidth of after installing NFE is 73.5 times wider than the bandwidth...
A broadband microstrip-line-fed circularly-polarized circular slot antenna is presented in this paper. The circularly polarized (CP) operation can be designed by embedding a spur slot into the circular slot and the broadband CP operation can be simply achieved by an open slot. From the experimental results, the 3-dB axial-ratio (AR) bandwidth can reach as large as 350 MHz (14.5% relative to the center...
A modified coplanar waveguide-fed slot dipole antenna with wideband harmonic suppression is proposed. The antenna consists of a capacitively excited coplanar waveguide-fed slot dipole and twelve slot stubs, of which half of them are added in each arm of the slot dipole. The proposed antenna shows a wideband harmonic suppression characteristic up to at least nine times of the operating frequency. Design...
Wideband circularly-polarized (CP) conical beam wheel-shaped antenna with a back reflector is presented in this paper. The wheel-shaped antenna composes of a center-fed monopolar patch which generates a vertically polarized electric field Eθ and eight coupling loops which radiate a horizontally polarized electric field Eϕ. Both fields have conical-shaped patterns and circular polarization is obtained...
This paper proposes dielectric lens-corrected horn with a coaxial groove. For covering a wider area with keeping a high gain, this paper newly proposes dielectric lens loaded into a horn antenna for wide angle radiation for 24 GHz radar systems. It can improve the lowest gain of the desired area by optimizing both parameters of the dielectric lens and the primary horn.
A dual polarization of patch antenna array for IEEE 802.11b/g/n MIMO applications are proposed and experimentally studied in this paper. The four by one patch antenna array printed on 300mm by 100mm by 0.8 mm FR4 substrate. The FR4 substrate is 2.5 mm above the metal ground plane. The patch array has two input ports for the orthogonal polarizations MIMO application. The measured efficiency and gain...
It is known that coupling between balanced and unbalanced modes on AUT (antenna under test), is calculated by using mixed-mode S parameters. In this paper, it is shown that the coupling can approximately be evaluated by proposed one-port measurement with a quadrature hybrid as well as two-port measurement for equivalent network of AUT.
For calibrating electric-field probe to evaluate the value of SAR (specific absorption rate) for devices at a frequency of 30 MHz, a shielded loop antenna is used as a reference antenna. To facilitate curve fitting for the calibration, near-field gain should be constant near the loop. In this paper, it is shown that the circumference of the loop can be selected as the near-field gain becomes approximately-constant...
This paper presents a design of a quasi-millimeter wave wideband antenna array consisting of a leaf-shaped bowtie antenna (LSBA) and series-parallel feed networks in which parallel strip and microstrip lines are employed. A 16-element LSBA array is designed such that the antenna array operates over the frequency band of 22–30GHz. In order to demonstrate the effective performance of the presented configuration,...
In this paper, we present a coupled-fed meandered loop antenna on a planar structure. The antenna is fabricated on the FR4 substrate of thickness of 1.6mm and permittivity of 4.4. The antenna with a total size of 30 mm × 13.75 mm × 1.6 mm is feed by a 50 Ohm mini-coaxial line. By using an L-shaped monopole connected on the coaxial line and the meander loop to generate multiple modes to form the required...
This paper describes characteristics of direct and scattered waves that are extracted from measurement channel data obtained using a 3.35 GHz vector channel sounder in an indoor environment. Each ray of the scattered waves is designated a number in order of the received level. The relationship between the ray number and the characteristics of each ray such as the received level, delay time, and azimuth...
In this paper, the data-rate evaluation results of passive multiple-input multiple-output (MIMO) transmission are presented. In the passive MIMO technique, the load modulation is used at the tag and multiple antennas enhances the data-rate without extending the frequency band. From the experimental result, it is shown that the proposed passive MIMO scheme actually achieves 1.6 Mbits/s by using 2×2...
Recently, the challenges of the utilization of higher frequency bands for cellular systems have been attracting attention. In these high frequency bands, besides the higher propagation losses, the propagation channel tends to suffer more severe shadowing by pedestrians in the environments. In this paper, we carried out measurements in the 26GHz band in an indoor quasi-static environment for figuring...
In this paper, the design of multiple loop antenna is presented for near-field UHF radio frequency identification (RFID) applications. The proposed antenna is operated at 920–925 MHz along the standard of the RFID frequency band in Thailand. The antenna can generate the magnetic field distribution in three principal directions in the operating area. The prototype antenna was fabricated on FR4 substrate...
A simple circularly polarized (CP) loop tag antenna is proposed to overcome the polarization mismatch problem between reader antenna and tag antenna. Good CP radiation can be achieved by introducing an open gap onto the square loop. Also, the technique of loading a matching stub across the RFID chip is applied to the proposed loop tag antenna, and desirable impedance matching between the antenna and...
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