X-band

We present two designs for X-band dual circular polarization transducers. The design uses all simple or existing shapes, and it will be easy to manufacture. This design has MHz operation bandwidth which is enough for our OMT application. This polarizer can be utilized for several motivations, including RHCP and LHCP signal broadcasting and receiving, high power RF loads and RF power compressors. ACKNOWLEDGMENT

Abstract: In order to correct attenuated millimeter-wavelength (Ka-band) radar data and address the problem of instability, an attenuation correction methodology (attenuation correction with variation trend constraint; VTC) was developed. Using synchronous observation conditions and multi-band radars, the VTC method adopts the variation trends of reflectivity in X-band radar data captured with wavelet transform as a constraint to adjust reflectivity factors of millimeter-wavelength radar. The correction was evaluated by comparing reflectivities obtained by millimeter-wavelength cloud radar and X-band weather radar. Experiments showed that attenuation was a major contributory factor in the different reflectivities of the two radars when relatively intense echoes exist, and the attenuation correction developed in this study significantly improved data quality for millimeter-wavelength radar. Reflectivity differences between the two radars were reduced and reflectivity correlations were enhanced. Errors caused by attenuation were eliminated, while variation details in the reflectivity factors were retained. The VTC method is superior to the bin-by-bin method in terms of correction amplitude and can be used for attenuation correction of shorter wavelength radar assisted by longer wavelength radar data.

Microwave is defined as the electromagnetic radiation with frequency range from 300MHz to 300 GHz that divided into some Frequency bands. X- band (8-12.5 GHz) is part of the radar frequency band in the microwave spectrum and descript as super high frequency. X-band frequency have various applications such as satellite, communications, radar, navigation, air traffic Control, marine and weather station and etc.[1]. Therefore, many workers are exposed to these waves. A study was conducted by American Navy about 40,581 soldiers. It determined that half of the soldiers were exposed to radar frequency[2]. This is an example of researches that showed many of the workers have exposure to X- band frequency. Uncontrolled exposure of microwave lead to thermal and non-thermal effects[1] . Cataracts, skin burns, and damage to the testes are some of thermal effects[1, 3]. Furthermore, the non-thermal effects of X-band frequency are very wide that including; Reproductive effects, cancers, blood effects, genetic, adverse immune effects and mental effects. Also, there are many unknown aspects of the biological effects that did not determined very well, such as oxidative stress and mental

Supriya Jana et al., 2012; Supriya Jana Bipadtaran Sinhamahapatra et al., 2013). The band and its slight variations contain frequency ranges that are used for many satellite communication transmissions, some Fi devices, cordless telephones, and weather radar systems Chakraborty et al., 2011; Jan and Tseng, et al., 2011). The X -band defined by an IEEE standard for radio waves and radar engineering with frequencies that ranges from 8.0 to 12.0 GHz respectively. The X band is used for short range tracking, missile guidance, nd air bone intercept (Supriya Jana and . Especially it is used for radar communication ranges roughly from 8.29 GHz to 11.4 GHz. The proposed antenna (substrate with ε r = 4.4) has a gain of

Abstract: In this paper, a novel design of inset-fed rectangular microstrip antenna is simulated, designed and optimized to get a Hexa-band operation frequency. The antenna top portion consists of a L-shaped slit loaded rectangular radiating patch and a H- shaped slot is loaded in the ground plane. This antenna is resonates at six different frequencies of 1.5 GHz, 2.4 GHz, 4.3 GHz, 5.5 GHz, 7.9 GHz and 9 GHz with -10 dB return loss having impedance bandwidths of BW1=13.33%, BW2=5% , BW3=6.5%, BW4=6% , BW5= 4.9% and BW6= 15.6%. The proposed antenna is fabricated on commercially available low cost FR-4 substrate with relative permittivity of 4.4 having physical size of 40 × 30 × 1.6 mm3. The antenna produces broadside nature radiation pattern with maximum gain of 5.68 dB. The antenna finds applications in GPS, WLAN and X-band communications. Keywords: Hexaband, L-shaped slit, GPS, WLAN,

A design of novel inset-fed circular microstrip antenna embedding an elliptical split ring slot is studied for penta-band frequency application. From the detailed experimental study, it is concluded that, a simple elliptical split ring slot at the radiating circular patch makes the antenna to operate for penta-band of frequencies with a maximum bandwidth of 12.8%. The proposed antenna shows broadside radiation pattern characteristic with a maximum gain of 7.18 dB. The proposed antenna is simple in its construction and is a low cost. Hence, the proposed antenna may finds application in wireless and X-band radar communications.

Abstract—An X-band radiator as an open-ended waveguide with a hybrid dielectric insert is proposed. The insert is in the form of a parallelepiped, which fills the entire cross section of the waveguide and constitutes a Teflon matrix with local inhomogeneities in the form of dielectric cylinders with a different permittivity. The design allows for forming various near-field distributions and, hence, the radiator performance by means of definite combinations of the local inhomogeneities can be modified. A number of configurations in the location of air and quartz cylinders are investigated. The calculated and experimental results are in good agreement. The proposed approach to the near-field formation of the aperture antenna is promising, because the variety of possible configurations in the location of local inhomogeneities with different permittivity provides new opportunities in terms of designing both single radiators and antenna arrays.

In this paper, a cascaded dual-layer wideband FSS reflector resonating at 5.2–15.6 GHz is presented. The percentage bandwidth obtained with the prototype structure in the proposed frequency range is 100% (almost double that of quoted designs). The advantages of this reflector are wide stopband of 10.4 GHz and simplicity of the design. The reflector marks its application in 4G, X-band and Ku-band. A prototype of a dual-layer FSS is fabricated, and the fabrication results agree well with the simulation results hence justifying the methodology of the proposed design.

A compact microstrip fed multiband monopole antenna for Bluetooth, UWB, X-band and Ku band applications is proposed and investigated. The dimensions of the central rectangular strip monopole which is responsible for resonate over Bluetooth band are investigated. Also the antenna design is optimized with two ground structures. The proposed ground scheme is an excellent approach, which makes a strong effect on the antenna’s impedance bandwidth enhancement for ultra-wideband and other applications. The results proved that the design stands out as a potential candidate for future UWB applications.

The unit cell of the absorber is shown in Fig. 1 with the dimensions listed in Table 1. The design started with two L-shaped patches facing each other with the longer sides coupled in a broadside manner. The structure returned a broadband absorption performance from 9 GHz to 16.8 GHz, having an absorptivity greater than 0.8 or 80% over the frequency range as shown in Fig. 3(a) (black dotted line). To improve the coupling between the patches a rectangular conductor strip is inserted between them, as the bandwidth widened from 7.9 GHz to 17.9 GHz as shown in Fig. 3(a) (red dash dotted line). To further improve the absorptivity and obtain a still higher bandwidth horizontal metallic strips of length ‘p’ and width ‘w’ are added over the horizontal arms of the L-shaped patches, hence to improve the capacitive coupling between two adjacent unit cells. This resulted in a further increase in the absorption bandwidth ranging from 7.92 GHz to 18.12 GHz, covering both the X-band and the Ku-band of operations as shown in Fig. 3(a) (blue solid line). The unit cell is developed on a substrate slab having dimensions 9 mm × 9 mm in length and breadth respectively. The dimensions are given below in Table 1.

In the present communication we report an investigation of Li substituted ferrite material which is prepared by Solid State Reaction Technique (SSRT) with considerations of antenna application. However no reports are available in literature on the influence of Ti in the Li substituted ferrite on the basis of X band antenna application requirements, while several studies have been reported with the addition of divalent, trivalent and tetravalent ions [5, 6]. In this paper an attempt has been made to manipulate properties of synthesized Li ferrite by doping Ti in view of nonreciprocal behavior of ferrites under magnetic field for antenna applications. Number of samples of same composition synthesized and investigated thoroughly for electric, magnetic and some physical properties.

The microwave oscillator with T- type resonator was designed, fabricated and characterized for X–band applications. The oscillator designed by using T- type resonator has very low phase noise as -113.77 dbc/Hz offsets with the output power of 21.54 dbm. The overall size, phase noise and output power level have been discussed. The proposed oscillator is possible to fabricate commercially at a lower cost and smaller size and it is ready to use in the X- band applications in microwave circuits.

Since size reduction is the main challenge of this work, the first step is to choose an appropriate layout with a minimal number of circuit elements. The proposed diagram is shown in Figure 1. The system is composed of two low noise amplifiers (LNAs), one X-band BPF, one image rejection mixer (IRM), one qudrature hybrid, one IF BPF and one IF amplifier. The LNA chips use HMC902; the IRM uses HMC520; the IF amplifier uses PW112.

Christina Lessi, Evangelia Karagianni designed an X band LNA for Marine Navigation RADAR and obtained a power gain of 15 dB and noise figure of 5 dB [1]. Tumay Kanar, Gabriel M. Rebeiz, designed cascaded low noise amplifiers using SiGe HBT for X

Once the unit cell is characterized, next task is to design a dual-band dual-pole bandpass filter. To insert another pole, two identical planar inserts are placed at a distance “l”, as shown in Fig. 6. In the figure, “h” indicates the thickness of the dielectric and copper cladding of the substrate. To analyse the coupling between the identical inserts and its effect on the frequency response of the filter, parametric analysis of the structure is carried out for different values of “l”. The result is shown in Fig. 7. It reveals that an acceptable frequency response can be achieved for l = 8.41 mm. It may be noted that this separation is approximately quarter wavelength long at the center of X-band (10 GHz). For TE 10 mode at 10 GHz, the guided wavelength of the propagating wave in dielectric (Roger RO4350

Abstract—This paper presents the design, fabrication, and measurement of triple band metamaterial absorber at 8 GHz, 10 GHz and 12 GHz which are in the X-band frequency range. The unit cell of the metamaterial consists of three concentric copper rings at different radii, printed on 0.8 mm thick FR4 substrate in order to obtain triple resonant frequencies. The highly symmetrical ring structure in nature makes this absorber insensitive to any polarization state of incident electromagnetic (EM) waves for normal incident waves. The proposed structure is capable to operate at wide variations angle of incident wave. The simulated result shows that the triple-band metamaterial absorber achieves high absorbance for normal incident electromagnetic waves of 97.33%, 91.84% and 90.08% at 8 GHz, 10 GHz and 12 GHz, respectively, when subjected to normal incident electromagnetic. With metamaterial absorber maintaining 50% of absorbance value, the corresponding full width half maximum (FWHM) are 5.61%, 2.90% and 2.33%. The operating angles in which the metamaterial structure can maintain 50% absorbance at TE mode and TM mode are 67 ◦ and 64 ◦ , respectively. The experimental result

A novel configuration for a dual-frequency antenna having a high frequency ratio (1 : 3 . 3) is proposed in this paper. A 2 × 2 antenna array at higher frequency (X-band) is used instead of single patch to achieve high gain. This configuration uses the antenna at lower frequency (S-band) as ground plane for antenna array at higher frequency (X-band) and saves space. It achieves bandwidth of 13.3% at S-band and 6.2% at X-band without any interference between the two bands. It gives gain of 7.5 dBi at 2.5 GHz and 10.5 dBi at 8.2 GHz. It has high isolation of better than 38 dB between the two bands, and the radiation pattern is stable over the bandwidth of the two frequency bands. The antenna is fabricated and tested, and measured results are in reasonable agreement with the simulated ones.

The various iterations of the proposed design model is given below. The simple microstrip patch antenna is shown in Antenna 1 in Fig 3. In this antenna structure the ground plane is not provided with defected ground structure. This antenna will resonate single frequency in X band. In second iteration the ground structure is modified with DGS and rectangular slot are provided in the middle and two strip of the antenna. The DGS are of circular ring slot. This antenna will resonate at triple frequency in X band. Finally slight modifications are done in the antenna structure. In third iteration extending the length of the rectangular slot in the middle towards the strip which acts as feed line to provide better performance in multiple band frequency of operation.

In our proposed model various parametric measurements needed to supplement the future fabrication of antenna has been studied in detail. Multiband antennas are found to be more effective in wide bandwidth characterises with MIMO (Multiple input multiple output) [3] and it can be adopted with TDMA based MAC structure to compact with 5G cellular networks [4]. A Printed Dipole Antenna Integrated with Dual-Band Balun designed for Dual-Band and Wideband Design [5] can be extended for higher frequencies. A Multiband Fractal smart antenna [6] for at least seven converged wireless network services, planar multilateral disc monopole antenna for ultra wideband (UWB) [7], rectangular tri-band patch antenna [8] with loaded elements based on genetic algorithm, Tri-band microstrip-line-fed low profile microstrip patch antenna [9] motivated to design a multiband antenna suitable for the application of C- Band, X-Band and 5G Cellular communications.

For designing wideband circularly polarized resonant cavity antenna, the PRS can be designed using simulation study or the model discussed above for the required band, e.g., in this case X band is considered. The center frequency of the positive reflection phase gradient should coincide with the required band’s center frequency. After that, the wideband circularly polarized microstrip antenna fed by branchline coupler is designed. The PRS is placed over this antenna at a height corresponding to the center frequency. The value of ‘h’ is optimized corresponding to the center frequency of 10 GHz and taken as 15 mm.