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A new low-loss quasi-transverse electromagnetic (TEM) microstrip line, called as a self-packaged microstrip line, is proposed for microwave and millimeter-wave applications. It is fully based on the low-cost PCB process, but without the issues of radiation and surface waves by using a top layer perfect magnetic conductor (PMC) substrate. The self-packaged microstrip line consists of three layer substrates:...
In this paper, a new all-fiber mode converter was proposed, which can achieve LP01 to LP02 mode conversion and vice versa. The proposed mode converter is based on a tapered core and four bipyramids combined structure with annular distribution; the tapered core is used to excite the high-order modes while the bipyramids combined structure curb the undesired high-order modes and make the LP02 dominate...
This paper proposes a novel multi-stub ultra-wide band planar monopole antenna. The radiation patch of the antenna is composed of a pair of back-to-back E-shape-like stub elements. The E-shape-like stub element is the extension of the E-shape stub element, adding two semi-circle elements at the back of the E-shape stub element and extending the top of the E-shape stub element with an inverted L-shape...
In this paper, a novel comprehensive transmitter architecture has been proposed, which enables the concurrent transmission of two separate frequency bands by carrier aggregation. For different frequencies, the proposed transmitter can simultaneously employ 1-bit Low-pass and Band-pass delta-sigma modulators structures, or employ hybrid structures. Carrier frequencies are equal to oversampling frequencies...
A small CPW fed triple band-notched (Ultra Wide Band) UWB antenna is presented. The proposed antenna consists of a shovel-shaped radiating patch with three C-shaped slots, a feed line and a modified ground plane. By etching three C-shaped slots with variable dimensions on the radiating patch, frequency band-stop performance is generated and we can control its band-notched frequency and bandwidth through...
In this paper, a new-version microstrip line is proposed, named packaged microstrip line. It is comprised of three dielectric substrates. This novel microstrip line is no longer suffering from the issues of radiation losses, surface waves, or cavity resonances that exist in the standard microstrip line without or with a metallic shielding box. Instead of the packaging way based on the standard air...
To miniaturize the conventional air gap waveguide (GW), a substrate integrated gap waveguide (SIGW) is proposed. Moreover, SIGW makes up the defects in the microstrip-ridge air GW, such as inconstant gap height, holes in strip, as well as strip electroless nickel immersion gold (ENIG) coating. To verify the proposed SIGW, a prototype was designed and manufactured using the multi-layer printed circuit...
A low-cost linearization technique is proposed to improve RF signal power and suppress third order intermodulation distortion (IMD3) in radio-over-fiber (RoF) transmission systems. A directly modulated laser (DML) and an electro-absorption modulator integrated laser (EML) in C-band are both used for optical subcarrier modulation. The IMD3s induced by the two optical subcarrier modulations are suppressed...
A novel coplanar waveguide (CPW)-fed compact ultrawideband (UWB) microstrip antenna is proposed for ultrawideband applications. By etching a mixed slots structure on the surface of the radiating patch, the area of it was greatly reduced and the impedance bandwidth was extended. The mixed slots include two semicircle and one rectangular slots. Similarly, through etching a pair of quarter-circle slots...
In this paper, a mode converter between mode LP01 and LP0m (m>1) is proposed based on two-stage tapered fiber. Each LP01-LP0m converter is obtained by changing the parameters of a generic structure. Three converters between LP01 and LP0m, m=2, 3, & 4, are designed for C-band, with less than 0.7-dB insertion loss and higher than 15 dB extinction ratio over the entire band.
A novel broadband analog predistortion circuit (PDC) is designed to linearize radio-over-fiber (RoF) systems. Dual Schottky diode is used as predistorter. The PDC with high bandwidth and small dimension is achieved by removing quarter-wavelength transformers and power dividers. Measured S-parameters show that the PDC can work from 10 MHz to up to 40 GHz. The PDC is verified using two-tone and WiFi...
A novel printed compact triple-band antenna for WLAN/WiMAX applications is proposed in this paper. Due to the coupling between the 'comb' shape parasitic element and the multi-branch radiating element, three frequency bands which are suitable for WLAN/WiMAX are achieved. The simulated results show that by adding the parasitic element, the high frequency end cutoff frequency of the antenna is reduced...
A linearization technique using two lasers with different wavelengths is further studied to improve output signal and suppress second and third order nonlinearities in radio-over-fiber (RoF) systems simultaneously, if an optical device or a subsystem generates nonlinear distortion and also has wavelength dependent transmission characteristic. In this paper, for an RoF system using an EAM that has...
Optical and electrical linearization techniques are reviewed for broadband radio over fiber transmission. The optical linearization includes optical mixed polarization and two-wavelength linearization, and the electrical linearization includes analog pre-distortion circuit. The optical linearization leads to more than 10-dB improvement of spur-free dynamic range (SFDR). The analog pre-distortion circuit...
A low-cost broadband predistortion circuit using zero bias diodes is designed to remove 3rd order intermodulation distortion of electro-absorption modulator in radio-over-fiber system. Experiments show that input power at 1-dB compression point is improved by 0.8–3.8 dB from 8 to 17 GHz; and spurious free dynamic range is improved by ∼9 dB from 7 to 14 GHz and ∼4 dB from 15 to 18 GHz, limited by 5...
A novel statistical model, called RM model, on the mobile channels is proposed. The envelope of the received signal is modeled as a Rician signal with exponent M. The Probability density function (PDF) in dB is derived by using signals in dB. The expectation of received signals (in dB) is in directly proportional to M.
A novel high isolation MIMO antenna for WLAN and WiMax operation is proposed. The proposed antenna consists of two back-to-back G-shaped monopoles placed symmetrically with respect to a mushroom-like EBG structure. The measured results show that the proposed MIMO antenna covers WLAN (2350–2550 MHz) and WiMax (3500–3690 MHz) bands with high isolation. The antenna can provide pattern diversity to combat...
A novel UWB antenna is presented, which is formed by the modified Sierpinski-carpet fractal with the 50Ω micro-strip. Four resonant frequencies and three operation frequency bands can be observed via measurement between 1GHz–20GHz when return loss is smaller than −10 dB. The bandwidth of lower frequency band is from 1.1GHz to 10.8 GHz.
We propose and investigate the suppression of RoF nonlinearity using a semiconductor optical amplifier combined with simplified mixed polarization. It is found that EVM of OFDM UWB can be improved by up to 10.2dB.
To further reduce the coupling of a MIMO antenna containing a mushroom-like EBG structure, we propose a novel MIMO antenna by using a fractal mushroom-like EBG structure to realize a high isolation. The simulated band width of the antenna is 2100 to 2830 MHz (S11<−10 dB), covering the bands of WLAN and WiMax. Compared to the antenna of using mushroom-like EBG structure, the antenna proposed in...
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