A Dual Band U‐Slot Printed Antenna Array for Lte and Wimax Applications

Abstract

gate P dark is calculated by R dark /f g . Figure 3 shows the relationships between detection efficiency, dark count, and after-pulse probabilities. The SPAD is cooled to 253 K and its breakdown voltage V b is 267.8 V at this temperature. The excess voltage over V b is tuned between 1-2 V to achieve different detection efficiency. The dark count and after-pulse probabilities are 1.06 3 10 25 per gate and 4.3%, respectively, when the detection efficiency is 13.9%.We fixed the amplitude of gating pulse and tune the threshold of discriminator to investigate the trend of detection efficiency and dark count probability. As shown in Figure 4, both the detection efficiency and the dark count probability increase when lower threshold is used. This is reasonable because lower threshold can let more avalanche pulses to be discriminated as detection events. The threshold we used is much lower than the peak value of spike as shown in Figure 2 which indicates the spikes have been well suppressed.We further evaluate the distribution of after-pulse probability with OSC. The OSC is triggered by a 5 MHz clock signal synchronized with the optical pulse. Detection events with different time delay are recorded and accumulated in time domain. Figure 5 shows the result when the detection efficiency is set to 13.9%. We can see the distribution of after-pulse probability approximately follows exponential decay and a total after-pulse probability of 4.3% is obtained.The after-pulse probability actually can be further improved if a short dead time is applied after a detection event is captured [4] with slightly degradation on the detection efficiency. It should be emphasized that as we match the SPAD simply with voltage adjusted variode, complex and expensive components such as the delay line, band elimination filter, microwave devices, or another identical matched SPAD are not needed. All the components can be integrated within a package of 15 3 15 3 6 cm 3 . CONCLUSIONWe have demonstrated a balanced single photon avalanche detector with spike noise cancellation based on tunable variode. At 253 K, detection efficiency of 13.9% is obtained with 1.06 3 10 25 per gate dark count probability and 4.3% after-pulse probability under 100 MHz gating frequency.ABSTRACT: In this article, a dual-band coaxial-fed 2 3 2 rectangular U-Slot microstrip patch antenna array for multiple input multiple output applications, in 4G long term evolution (LTE) and WiMAX systems, is presented. The targeted frequency bands are: (1) LTE Band-1 at 2.

Ultra‐wideband antenna for wearable Internet of Things devices and wireless body area network applications

“…A simple MPA resonates at one frequency band because of the fringing field effects between radiating patch and ground plane. By changing its current path because of the insertion of different slots or stubs, this MPA can be made to cover different frequencies . The MPAs have generally narrow‐band characteristics having lower gain .…”

A 1 × 2 triple‐band printed antenna array for use in next generation flying AD‐HOC networks (FANETs)

“…Although, patch antennas inherently offer low bandwidth and gain which are the main requirements for UAV communication in FANETs. A number of techniques have been proposed in the literature to overcome these shortcomings in the MPA design.…”

Analysis of T-Slot Loaded Disk Patch Antenna for Dual Band Operation with Small Frequency Ratio

“…However, these reported antenna structures of reactive loading using slots [11][12][13][14][15][16][17][18][19] involve complex calculation, design, higher frequency ratio and lower bandwidth as compared to proposed antenna. This has been summarized in Table 1.…”