A novel approach is proposed for building a planar array derived from linear arrays using a toolbox of different types of subarrays located parallel and perpendicular to the linear array axes. The array design assumes constant element patterns and focuses on rectangular array applications with one dimensional, wide-angular beam scanning. Optimization criteria concern a trade-off between side lobe level performance, directive gain scan-loss, reducing the number of element controls and maximizing the use of phase-only elements for beam steering. All subarray configurations and functionalities, for improving the full array performance in sidelobe level and scan-loss compensation, are analyzed and validated in detail. The step-by-step integration of different subarrays starts from the center part of the array. This center part is a linear subarray along the major axis of the rectangular array with uniform maximum amplitude and spatially stretched. This subarray is combined with cross-line subarrays perpendicular to this center axis. At both edges of the center array, two in-line, uniform-amplitude and stretched subarrays are added and combined with cross-line subarrays. The amplitude distribution of the 3 in-line subarrays and the cross-line subarrays allows for lowering the sidelobe level in the plane of scanning. Finally, at both ends of the three in-line subarrays, subarrays with two and five elements are applied for reducing the scan-loss. By assuming cos(artheta) element pattern results are given for a planar rectangular array with 41 elements length and 3 elements width. To lower cost and higher power efficiency, the array uses only 33 multi-bit phase shifters, 12 1-bit phase switches, and 4 attenuators for amplitude control. Optimized broadside and 60° scanning patterns are compared and show improved performance in directive gain D=24.4 dBi (broadside), D=19.9 dBi (60°) and in ext {SLL}=-21.6 dB (broadside), ext {SLL}=-19.5 dB (60°). @en

The scanning performance of wide-angular scanning linear arrays is primarily degraded by the limited angular profile of the employed elements' patterns. This paper introduces an innovative strategy for compensating this degradation by using subarrays. Our design uses a uniform linear array with half-wavelength spaced elements, supplemented by subarrays that are symmetrically placed at its edges. The employed subarrays have controlled patterns, favoring some directions for effective scan-loss compensation (SLC) and suppressing other directions for lowering the sidelobes level (SLL). Two types of feeding configurations, making use of fixed power dividers in combination with 1-bit phase switch, are used for producing the desired patterns. The complete array design and physical validation, starting from the elements, continuing with the subarrays and ending with the system integration are also discussed in detail. The integration of the subarrays yields notable performance improvements at large scanning angles when compared with uniform linear arrays. The peak and first SLL of -14.1 dB, and the SLC of 2 dB are obtained when the array with CUP antennas as elements is scanned to the maximum scan angle direction.@en

Passive multifrequency microwave sensors frequently struggle with difficulties of nonuniform spatial resolution among multiple channels. The raw measurements in the land-sea transition zone are seriously contaminated. Conventional analytical deconvolution techniques suffer from the tradeoff between spatial resolution enhancement and noise amplification, leading to low data integrity in the practical spatial resolution matching application. To provide multichannel microwave radiometer (MWR) data with matching levels of spatial resolution, a method based on iterative deconvolution with close loop priors (ICLP) is proposed. Specifically, a destriping module is first utilized as a preprocessing step to maintain high data integrity. Then, the close loop mechanism using sparse adaptive priors is proposed to balance the spatial resolution and data integrity enhancement. Also, progressively iterative deconvolution is introduced to realize controllable levels of spatial resolution enhancement (spatial resolution matching) for multichannel data to reach a consistent level. Experiments performed using both simulated and actual microwave radiation imager (MWRI) data demonstrate the validity and effectiveness of the method.@en

The main goal of theis article are investigation of impact of parsitic (common mode) currents on UWB antenna performance and study on possible desgins of UWB baluns. This reserach is carries out on one of popular designs of UWB antenna for impulse radio, namely elliptically shaped dipole. Computational model for investigation common mode and differential mode currents was built. It was shown that the commmon and differential mode currents have similar value fo this type of antenna. To decrease inflluence of the common mode current on the antenna a new feeding circuit has been designed. Theoretical results have been verified experimentally.@en

The main goal of theis article are investigation of impact of parsitic (common mode) currents on UWB antenna performance and study on possible desgins of UWB baluns. This reserach is carries out on one of popular designs of UWB antenna for impulse radio, namely elliptically shaped dipole. Computational model for investigation common mode and differential mode currents was built. It was shown that the commmon and differential mode currents have similar value fo this type of antenna. To decrease inflluence of the common mode current on the antenna a new feeding circuit has been designed. Theoretical results have been verified experimentally.@en

The main goal of theis article are investigation of impact of parsitic (common mode) currents on UWB antenna performance and study on possible desgins of UWB baluns. This reserach is carries out on one of popular designs of UWB antenna for impulse radio, namely elliptically shaped dipole. Computational model for investigation common mode and differential mode currents was built. It was shown that the commmon and differential mode currents have similar value fo this type of antenna. To decrease inflluence of the common mode current on the antenna a new feeding circuit has been designed. Theoretical results have been verified experimentally.@en

Space-Time Coding (STC) was designed with restrictions. The first one is that it shoulb be applied to independent flat fading channels. If the flat fading condition is not satisfied time-delayed multipath channels will introduce intersymbol interference (ISI). In this paper a new STC scheme is introduced that enhances the performance in channels with ISI compared to the original STC scheme. The second restriction of independently fading channels is also studied. In this work simulations of the performance of the new STC scheme in spatially correlated Rayleigh fading channels with ISI are performed and the results are presented. A diversity gain of 10 dB compared to systems without STC is achieved. For low time-delays in the propagation channel spatial correlation has a significant influence on the performance.At time-delays greater than a half a bit period the influence of spatial correlation is negligible.@en

Space-Time Coding (STC) was designed with restrictions. The first one is that it shoulb be applied to independent flat fading channels. If the flat fading condition is not satisfied time-delayed multipath channels will introduce intersymbol interference (ISI). In this paper a new STC scheme is introduced that enhances the performance in channels with ISI compared to the original STC scheme. The second restriction of independently fading channels is also studied. In this work simulations of the performance of the new STC scheme in spatially correlated Rayleigh fading channels with ISI are performed and the results are presented. A diversity gain of 10 dB compared to systems without STC is achieved. For low time-delays in the propagation channel spatial correlation has a significant influence on the performance.At time-delays greater than a half a bit period the influence of spatial correlation is negligible.@en

Space-Time Coding (STC) was designed with restrictions. The first one is that it shoulb be applied to independent flat fading channels. If the flat fading condition is not satisfied time-delayed multipath channels will introduce intersymbol interference (ISI). In this paper a new STC scheme is introduced that enhances the performance in channels with ISI compared to the original STC scheme. The second restriction of independently fading channels is also studied. In this work simulations of the performance of the new STC scheme in spatially correlated Rayleigh fading channels with ISI are performed and the results are presented. A diversity gain of 10 dB compared to systems without STC is achieved. For low time-delays in the propagation channel spatial correlation has a significant influence on the performance.At time-delays greater than a half a bit period the influence of spatial correlation is negligible.@en

The linear array performance of an ultrawideband (UWB), coplanar waveguide (CPW) fed, printed, loop antenna is investigated by means of simulations and measurements. The UWB properties of the array are demonstrated by synthesizing the array reflection coefficient, starting from the simulated and measured scattering matrices. The array is proven to have a VSWR ¿ 2 fractional impedance bandwidth of 64%, stretching between 7 GHz and 13.6 GHz. The performance of a complete, non-scanning, broadside array are examined by feeding the array via a Wilkinson power divider. The study is completed by radiation pattern measurements that show stable co-polar and low cross-polar characteristics over the operational bandwidth.@en

The design aspects concerning the sparse array antennas are discussed. Commonly, the beamwidth, the side-lobes level and the gain are the relevant features in antenna design procedures. These parameters are evaluated for different sparse topologies and generalised design relations are provided. The capabilities of sparse architectures are evaluated by comparision with uniform arrays for a similar level of performance.@en

The design aspects concerning the sparse array antennas are discussed. Commonly, the beamwidth, the side-lobes level and the gain are the relevant features in antenna design procedures. These parameters are evaluated for different sparse topologies and generalised design relations are provided. The capabilities of sparse architectures are evaluated by comparision with uniform arrays for a similar level of performance.@en

The design aspects concerning the sparse array antennas are discussed. Commonly, the beamwidth, the side-lobes level and the gain are the relevant features in antenna design procedures. These parameters are evaluated for different sparse topologies and generalised design relations are provided. The capabilities of sparse architectures are evaluated by comparision with uniform arrays for a similar level of performance.@en

In this paper, an array-based Groudn Penetrating Radar sensor to be used within a vehicle-mounted multi-sensor system for humanitarian demining is described. The radar front-end is built using time domain video impulse tefchnology. The main novelty of the radar is its antenna array, which consists of a singel transmit antenna and an array, whihc consists of a singel transmit antenna and a array of receive antennas. This approach satisfies contradictory demands of a large swath and dense measurement grid. First measurement results confirm validity of the suggested concept.@en

In this paper, an array-based Groudn Penetrating Radar sensor to be used within a vehicle-mounted multi-sensor system for humanitarian demining is described. The radar front-end is built using time domain video impulse tefchnology. The main novelty of the radar is its antenna array, which consists of a singel transmit antenna and an array, whihc consists of a singel transmit antenna and a array of receive antennas. This approach satisfies contradictory demands of a large swath and dense measurement grid. First measurement results confirm validity of the suggested concept.@en

In this paper, an array-based Groudn Penetrating Radar sensor to be used within a vehicle-mounted multi-sensor system for humanitarian demining is described. The radar front-end is built using time domain video impulse tefchnology. The main novelty of the radar is its antenna array, which consists of a singel transmit antenna and an array, whihc consists of a singel transmit antenna and a array of receive antennas. This approach satisfies contradictory demands of a large swath and dense measurement grid. First measurement results confirm validity of the suggested concept.@en

In this paper, an array-based Groudn Penetrating Radar sensor to be used within a vehicle-mounted multi-sensor system for humanitarian demining is described. The radar front-end is built using time domain video impulse tefchnology. The main novelty of the radar is its antenna array, which consists of a singel transmit antenna and an array, whihc consists of a singel transmit antenna and a array of receive antennas. This approach satisfies contradictory demands of a large swath and dense measurement grid. First measurement results confirm validity of the suggested concept.@en

Experimental data got in TUCSR show that out-of-diagonal elements of BSM measured sequentially are not equal. It is the evidence of errors and proves the necessity to measure all BSM elements simultaneously. Possibility of such measurements show experimental data got in IRCTR TUDelft, that show good isolation of orthogonal receiving channels in case of suitable radar signals bases.@en

Experimental data got in TUCSR show that out-of-diagonal elements of BSM measured sequentially are not equal. It is the evidence of errors and proves the necessity to measure all BSM elements simultaneously. Possibility of such measurements show experimental data got in IRCTR TUDelft, that show good isolation of orthogonal receiving channels in case of suitable radar signals bases.@en

Experimental data got in TUCSR show that out-of-diagonal elements of BSM measured sequentially are not equal. It is the evidence of errors and proves the necessity to measure all BSM elements simultaneously. Possibility of such measurements show experimental data got in IRCTR TUDelft, that show good isolation of orthogonal receiving channels in case of suitable radar signals bases.@en