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Abstract-In this paper, an ultra high frequency (UHF) low-profile antenna is proposed; it is based on the discone antenna but with addition of a back cavity, a short-circuiting structure and a two-plate top structure in order to achieve both low-profile and wideband. It is simulated and prototyped. The test results show that the antenna has an omni-directional radiation pattern in the horizontal plane, is of low-profile, has a height of less than 0.1λ max , and is wideband with an impedance bandwidth of 65% from 430 MHz to 845 MHz for VSWR < 2.5 and an impedance bandwidth of 43% from 440 MHz to 680 MHz for VSWR < 2.0. The proposed antenna can be easily flushmounted on a planar surface and therefore has great potential for uses on aircrafts and high-speed trains due to its conformal capability.

Digital radio-over-fibre transmission has been studied extensively as a way of providing seamless last-mile wireless connectivity by carrying digitised radio frequency (RF) services over broadband optical infrastructures. With the growing demand on wireless capacity and the number of wireless services, a key challenge is the enormous scale of the digital data generated after the digitisation process. In turn, this leads to optical links needing to have very large capacity and hence, high capital expenditure (CAPEX). In this paper, we firstly present and then experimentally demonstrate a multiservice DRoF system for a neutral-host fronthaul link where both forward and reverse links use data compression, multiband multiplexing and synchronisation algorithms. The effect of a novel digital automatic gain control (DAGC) is comprehensively analysed to show an improved RF dynamic range alongside bit rate reduction. In this case, the system allows all cellular services from the three Chinese mobile network operators (MNOs) to be converged onto a single fiber infrastructure. We successfully demonstrate 14 wireless channels over a 10Gbps 20km optical link for indoor and outdoor wireless coverage, showing a minimum error value magnitude (EVM) of <8% and >60dB RF dynamic range. It is believed that the technology provides an ideal solution for last-mile wireless coverage in 5G and beyond. INDEX TERMS Digital radio over fiber, neutral host, cloud radio access network (C-RAN), multiband multiplexing, automatic gain control, 4G, 5G, fronthaul.

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A planar monopole antenna with a parasitic shorted strip for multistandard handheld terminal is presented. The proposed antenna simply consists of two overlapping strips: a long strip on the front side and a parasitic shorted strip on the back side. To make the proposed antenna easy to manufacture and reduce the manufacturing cost, the entire structure is fully printed without VIA holes, the long strip monopole is directly fed, and the parasitic shorted strip is coupled-fed by the overlapped part. For lower and middle frequencies, the GSM900 and PCS bands are excited by the fundamental mode of the long strip and the parasitic shorted strip, respectively. For the upper frequency, the Wi-Fi2400/RFID2450 and LTE2300/2500 bands are provided by the third-order mode of the long strip. The detailed design of the proposed antenna and its radiation performances are studied. The proposed multiband antenna occupies a small area of 40 × 18 mm 2 on a printed circuit board (PCB). The measured results show that the proposed antenna has three impedance bands with return loss less than −6 dB: 25.6% for the low band (850-1100 MHz), 13.3% for the middle band (1750-2000 MHz) and 22.7% for the high band (2190-2750 MHz). INDEX TERMS Planar monopole antenna, parasitic shorted strip, coupled-fed, handheld terminals, multiband operation.

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